Odd Misfire/Slip

[40oz]

Most common issue after washing the motor is getting water in the spark plug wells and ruining the COP's. I would tell you to start there, however it only happening over a bump does not work out with that logic.

As trinity stated above, it is most likely an electrical problem. Do yourself a favor and don't wash the motor anymore.

Water won't hurt a COP. Oil will. I've washed my engine numerous times, at least once a year for the last 6 years, and never had a problem. But several years ago a rapid oil change place cut the filter when putting it on and blew oil all over under my hood. One COP got doused and began misfiring. The oil degrades the rubber insulation and allows it to short against the motor under load.

Afer replacing the COP, I washed the engine with Simple Green and soap and water and a hose to get all the oil off. And resolved to never again let minimum wage slaves change my oil

 

[joshjwc9]

Have you pulled all of the COP's to check the boots for odd tears? Is there any stored codes in the ECU for a misfire? I had a strange issue way back when and I had a boot that was beginning to tear, making the spark arch to the block and misfire on occasion. Remember you can just buy a boot for the COP at the part store too.

I've washed my motor once a month for the past few years. Using simple green and avoiding direct water on the alternator, main harness and COP's and I haven't had any issues. Although I do not pressure wash mine, I just use the garden hose.

 

[Nick388]

Have you pulled all of the COP's to check the boots for odd tears? Is there any stored codes in the ECU for a misfire? I had a strange issue way back when and I had a boot that was beginning to tear, making the spark arch to the block and misfire on occasion. Remember you can just buy a boot for the COP at the part store too.

I've washed my motor once a month for the past few years. Using simple green and avoiding direct water on the alternator, main harness and COP's and I haven't had any issues. Although I do not pressure wash mine, I just use the garden hose.

I pulled a few of the easier ones, including one where I decided to replace the whole COP. But with what you and 40oz, I'm going to go out in a about an hour or so (bad migraine atm) and check all 8 out.

I washed my engine the same way you did (bag over battery, alt and air intake as well), but I did have a code for a misfire then, but that coil is no longer in there. It was the coil because I switched it with another and the code followed. Funny thing was I took it out, WD-40'ed it and used some MAF Sensor cleaner on it, tossed it back in and didn't have a code, but regardless, I've opted to keep it out while chasing this problem. I checked for codes this morning, none present or pending.

Also checked injectors and all seem to be ticking perfectly normal. First thing I'll do when I go back out is check all 8 coils and if they seem okay (as well as inside the wells) I'm going to pull the spark plugs as well and check for damage or anything improper. Thank you for the tips!

 

[Nick388]

Okay, so I pulled all of the coils and they all seem fine. Cleaned them up a little, put them back in and the problem is still there. I took it over a really bumpy part of the road to see how it would do, and she stuttered a good 5 times or so and I got the tach and speedo to both go to "0" and back up as well as the theft light to re-blink it's code out.

I talked to my girlfriends dad who is a mechanic (ran his own shop about 8 years ago or so, he's a good guy) and he said it does seem like a ground issue unless I'm losing performance, then it seems like an engine controls issue. However, it's hard to really say whether or not I'm "losing power" because it's bucking so obviously I can't just "floor through it". Could this be some sort of short in the cables going to/from the transmission since this is effecting my tach and speedo on occasion? Also, how can I read/understand the theft lights code it's blinking out to me?

Edit: Found this article: http://www.fordscorpio.co.uk/pats.htm and if I'm understanding it correctly, I'm getting the 1:6 code which I'm assuming is one slow blink to six fast blinks (a total of seven blinks before it repeats itself). Now, is this my entire problem or a symptom of something else? Could a "Faulty link between PATS module and EECV" cause RPMs and Speed to temporarily, for a split second, read 0 and then sprint back up to where they were and cause the car to hesitate over speed bumps? Keep in mind, my car has never cut off on me when this happens. Or could it be something more upstream that is causing an error reading the key when the car bounces and causes the PATS to act up?

 

[midnightdriver]

I don't know if this would help at all, but do you have more than 1 key? I ask because I have heard of stories where the key has gone bad causing the PATS to go haywire. I know you can tune off the PATS with a custom tune or by FORD for new keys. Might want to try to disable, the PATS system and see if the issue continues, thats what I would do next.

 

[Nick388]

I don't know if this would help at all, but do you have more than 1 key? I ask because I have heard of stories where the key has gone bad causing the PATS to go haywire. I know you can tune off the PATS with a custom tune or by FORD for new keys. Might want to try to disable, the PATS system and see if the issue continues, thats what I would do next.

To be honest, I was JUST thinking this myself. I do have another key, so I'm going to give that a shot and see what happens. I do not have a tuner, is there another way to turn off the PATS if the issue still persists with the other key?

 

[joshjwc9]

If the COP's and boots are good, I'd start by unbolting the harness in the engine bay and blowing compressed air in there. Maybe some heavy moisture got in there too.

Sounds like there is a ground issue or battery problem. How old is the battery and where do you live? Some hot states, like here in FL, will go through batteries alot quicker if they sit awhile.

 

[Nick388]

Okay, so here's a few updates. I tried the other key and still got a few hesitations. Although they were less and I didn't get the tach/speedo/theft light while going over the same crap pavement that caused it last time.

So you guys asked for codes and I was under the impression you meant check engine light (there isn't one). However, I just figured out the cluster has a self-diagnostics thing that can store it's own codes (or something like that). I checked into it and I have three codes stored there which came up as dtc5284, dtcd147, and dtcd262 (this is exactly how the dash showed them). From what I understand, the 5284 is a common code and isn't anything to worry about according to PaladinMicro (click on "Repair and Maintenance" and then "Instrument Cluster Diag"). I haven't found too much on these D related codes besides here: DTC Codes - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars but it doesn't go into fixing them or why they appear.

If the COP's and boots are good, I'd start by unbolting the harness in the engine bay and blowing compressed air in there. Maybe some heavy moisture got in there too.

Sounds like there is a ground issue or battery problem. How old is the battery and where do you live? Some hot states, like here in FL, will go through batteries alot quicker if they sit awhile.

I (and the car) lived in Maryland until 7 months ago. I moved to CA in October but have been driving it regularly, at most it's sat for 5-6 days. Could you explain a little more about unbolting the harness? Which harness and where is it located? This electrical stuff is new to me.

If it is a battery issue, can't I just use a voltmeter (or whatever it's called) to test it? I have one in the other room, just don't know what it should test at and under what rules (ie, does the car have to be on or off?).

 

[joshjwc9]

Get the car to a parts store, they can usually check for proper resistance within the battery. Although if the car doesn't have a good charge it will usually be evident by a longer cranking time when it is cold.

If you look at your engine, up against the firewall right by the passenger fender you will see a harness with a bolt. Take the bolt off and just take some compressed air to it.

The cluster codes are not related to the CEL codes. The cluster codes are something else that I don't know about.

This all happened after washing the engine? Do you have a CAI that might have gotten wet, or led to the MAF getting wet? Something like this is hard to diagnose over the internet...

 

[Nick388]

Get the car to a parts store, they can usually check for proper resistance within the battery. Although if the car doesn't have a good charge it will usually be evident by a longer cranking time when it is cold.

If you look at your engine, up against the firewall right by the passenger fender you will see a harness with a bolt. Take the bolt off and just take some compressed air to it.

The cluster codes are not related to the CEL codes. The cluster codes are something else that I don't know about.

This all happened after washing the engine? Do you have a CAI that might have gotten wet, or led to the MAF getting wet? Something like this is hard to diagnose over the internet...

Yeah, I completely understand. Usually I can just search and find something, but I really couldn't find too much relating to the issue I'm having.

From what I can remember (I have a bad memory and this was over a month ago now), this did start acting up about after the time I washed it, but it also sat the week after I washed it (iirc). I covered the CAI, so that SHOULDN'T have gotten wet (felt dry afterwards). I'm not sure what the led to the MAF is though, if you mean just the MAF/MAF wiring, that should have been fine too, as I didn't even spray in that direction.

I'll be sure to check the wiring harness you mentioned. Thanks for the tips!

 

[Nick388]

Okay, so this is definitely something electrical. I threw a CEL and was hoping "Good, whatever wasn't working just broke and I can just replace it", but no, not that easy! I pull the codes and got P1451 and P1409 and then I had P0443, P0135, P0141, P0155, and P0161 pending. So naturally, all of this didn't die at once, so I checked a fuse and sure enough the F2.8 for engine controls. This is the third time now since I've experienced this problem, so it has to lie somewhere dealing with this fuse. I replaced the fuse, put the key to the on position and it didn't blow, so I'm assuming it is related to the bumps causing it to hit something and/or ground.

Can anyone make a connection with a car hesitating over bumps, theft light coming on with a 6:1 flash code, speedo/tach dropping to zero and immediately back up and with this fuse F2.8 under the dash? I'm going to check the O2 wiring this weekend

Edit: I noticed the Service Engine Soon light on my way home from work. While it was on, I noticed it did NOT do the hesitation, so I'm assuming this is 100% related at this point.

 

[Nick388]

I double checked a lot of wiring in the engine compartment yesterday and I actually found a loom behind the DPFE bracket that was burnt through. It was facing down and was burning/rubbing on some sort of pipe that was covered with the worse kind of crap (protective covering) that was really just falling apart. I ended up having to cut some of the loom off to expose the wiring so I could fix them. I ended up repairing a good 4 or 5 wires with exposed copper. I rerouted the loom (after properly repairing it, of course) so it wouldn't rub against this pipe anymore (still have no idea what it is.. AC/heat related I would have to guess). Nothing four thick, yellow zip ties couldn't handle. I heard yellow zip ties add 5hp per anyways.

Regardless, issue solved! Good luck to everyone not having this happen to them, it was kind of a pita to troubleshoot, though seemed so simple once I found it.

 

[midnightdriver]

I double checked a lot of wiring in the engine compartment yesterday and I actually found a loom behind the DPFE bracket that was burnt through. It was facing down and was burning/rubbing on some sort of pipe that was covered with the worse kind of crap (protective covering) that was really just falling apart. I ended up having to cut some of the loom off to expose the wiring so I could fix them. I ended up repairing a good 4 or 5 wires with exposed copper. I rerouted the loom (after properly repairing it, of course) so it wouldn't rub against this pipe anymore (still have no idea what it is.. AC/heat related I would have to guess). Nothing four thick, yellow zip ties couldn't handle. I heard yellow zip ties add 5hp per anyways.

Regardless, issue solved! Good luck to everyone not having this happen to them, it was kind of a pita to troubleshoot, though seemed so simple once I found it.

 

[trinity_gt]

I double checked a lot of wiring in the engine compartment yesterday and I actually found a loom behind the DPFE bracket that was burnt through. It was facing down and was burning/rubbing on some sort of pipe that was covered with the worse kind of crap (protective covering) that was really just falling apart. I ended up having to cut some of the loom off to expose the wiring so I could fix them. I ended up repairing a good 4 or 5 wires with exposed copper. I rerouted the loom (after properly repairing it, of course) so it wouldn't rub against this pipe anymore (still have no idea what it is.. AC/heat related I would have to guess). Nothing four thick, yellow zip ties couldn't handle. I heard yellow zip ties add 5hp per anyways.

Regardless, issue solved! Good luck to everyone not having this happen to them, it was kind of a pita to troubleshoot, though seemed so simple once I found it.

Good work!

That pipe is the EGR tube (the end of it goes to the EGR valve on the upper plenum) and the mesh is supposed to be a simple heat shield, probably to protect against inadvertent touches by techs. It's really a poopy design that seems to rely only on the mesh to prevent direct contact with a part that could be nearly as hot as an exhaust manifold. Ford should have known better.

 

[Nick388]

Ah, thanks Trinity! It's always good to learn what things are called, instead of doing what I did .

Just for future reference (never know if anyone will find this in the future), I found the problem by simply using a voltmeter set to ohms. I started at the EGR solenoid connector, since it's located the furthest back on the connection on the fuse that was blowing (Fuse 2.8, or Fuse #8 of the interior box). From what I understand (I could be slightly wrong with this) but red wires with a yellow stripe are connected to this fuse. Even though multiple connectors (including coil on plugs) have this wire, they get their power from another source and just the sensors are actually powered by this fuse. Again, since the EGR solenoid is the furthest back on the power connection, I started there with my ohm testing and was able to determine that I had a reading (a small one, yet a reading!) of a few ohms, meaning that somewhere on that line it was open. I unplugged it at the connection someone mentioned to me earlier in the thread in the corner of the back, passenger side of the engine (literally stuffed back there in the corner) and retested for power at the EGR solenoid and both (female and male) sides of the connection. I was still getting power on the EGR solenoid side of the connection meaning I had the short on that side (so interior side was okay!). Started feeling the connection back, moving and jiggling the harness and all of sudden, what do you know? I didn't have a reading anymore, meaning I had jiggled the short away from where it was shorting. After that, it was feeling for the open in the harness and then making my repair.

Hope that makes sense for anyone who is experiencing this or may experience this in the future and runs across this thread. I'm sure someone will chime in with a little more technical stuff and to make corrections to what I said earlier in this post (as I'm sure I'm sliiightly off here and there).

Thanks for making me realize this was an electrical issue, I was certainly VERY confused at first. Feels great not having to get off the gas over bumps now! lol

 

[MaxedGT]

Wire 1
Wire 2
Wire 3
Wire 4

Okay, there are the images. I couldn't figure out how to resize the images, so I just linked to them. Yes, I know my fusebox cover is off, I was checking fuses too. The black wire running to the 30A fuse is just for my radar detector when I use it, it's been hooked up for years, so I know that's not it .

I know the pictures aren't the best but I'm sure you get the idea of where it's located. The brown/copper color is the exposed wiring of one wire, then there's an exposed silver wire and solder connecting the two. I wanted to short them on something just to check, but for obvious reasons I don't want to go grounding random wires. I can't find too much else for concern under the dash, but I'm going to head back out in a few minutes to see what I can find.

That black wire stuffed into the fuse block like that is really a bad idea. I've seen people do that and cause the same type of symptoms you're describing. Stuffing the wire in there spreds the contacts in the fuse panel and causes a poor connection. With the engine running try wiggling that fuse and even gently pulling on it.