Satan causes intermittent power loss/bucking?

Discussion in 'Fox 5.0 Mustang Tech' started by Darkwriter77, Aug 15, 2005.

  1. ARGHH!!! I'm running out of things to clean/check/replace, here. For any resident 5.0L exorcists, here's my current demonic possession:

    Cold or warm, the car has an issue with surging/bucking at cruise and losing about 25% of its power at WOT. There is the occasional small mini-backfire out the exhaust during these little fits of the herky-jerkies, which I figure is caused by a rich-running condition. Except during periods of Satanic influence, the car idles fine; otherwise, while possessed, the car idles almost like I'm running a lopey cam. This presence of evil isn't constant, and it seems to come and go without any rhyme or reason, totally independant of ambient or engine temps, driving habits or distance, humidity, etc.

    This sort of thing has happened off and on since I obtained the vehicle about four months ago, but it was initially due to a severely clogged PCV screen/valve, disconnected/rotting/split vacuum lines, and/or a dire need for a tune-up. Since then, partly due to these random symptoms and partly because I'm totally OCD about making things run perfectly, I have dumped the following blood, sweat, and tears into this apparent target of El Diablo:

    -Replaced EGR valve and cleaned passages
    -Replaced IAC and cleaned passages
    -Replaced all 8 injectors with new 19# four-hole units from 4.6L T-bird (due to 3 cracked/leaky stock units)
    -Replaced cap/rotor (brass), wires (Bosch), plugs (Motorcraft)
    -Replaced all filters/fluids - air, oil, fuel, rear diff., tranny, etc.
    -Given two Seafoam treatments through PCV valve and gas tank, and hosed the snot out of the throttle body/upper intake with Seafoam Deep Creep
    -Adjusted TPS voltage
    -Replaced every little piece of rubber vacuum line, checked all hard plastic lines for leaks with carb cleaner and watchful eyes
    -Replaced PCV valve grommet and screen
    -Cleaned up every ground connection in sight
    -MAF wires cleaned and reset ECM
    -No trouble codes found, no CEL coming on

    All of this has been going on since the day I drove the beast home ... with the evil influence of The Beast hiding under the hood with it, apparently. :(

    Any suggestions/ideas/chants of divinity shall be met with bowing at thy feet and much gratitude (up to and including the kissing of feet). :hail2:
  2. Are you losing any fluid? Or blowing any smoke from the tails? I assume you would have mentioned this but i thought i would ask. Is it speed density? Your map sensor could cause this demonic possesion if it is.
  3. Nope, not SD-equipped ... otherwise I wouldn't have had any MAF wires to clean. :D

    Fluid loss, sure, but nothing major. Need to replace the O-ring around the VSS unit that plugs into the side of the tranny, as that's dripping just enough DexIII onto my hot cats to make a horrid stink. Not dripping/burning any motor oil, not losing any coolant.

    I suppose the MAP sensor is about the only thing I haven't toyed with or replaced yet, but they're a bit pricey for me to just go pick one up and HOPE it does the trick. Ye Olde Chilton manual isn't much help for diagnosing these sorts of things.

    Oddly enough, while playing the last track of the Pulp Fiction soundtrack whilest driving, the car acted up again. Its ill reaction to the recitation of scripture seems to verify my suspicion that Satan is at fault... :scratch:
  4. Got to looking into the BAP issue more, and that sounds to be the only stone left unturned. Symptoms other describe seem about the same as mine, to an extent. Got a BAP sensor on order now (and wasn't aware of the MAP/BAP difference 'till I got around to matching up OEM numbers to aftermarket ones at the parts counter), and it should be in my grubby hands by tomorrow. Will post results of this latest exorcism attempt. Many thanks for the suggestion, Darthcual.
  5. off topic sort of but i love your extended metaphorical use of satan as the problem of your car... creative and entertaining

    anyway.... sorry dude, had the same exact problem with my 84, bucking and missing, replaced soo many parts and cleaned up soo many things...

    only satan loved to toy with me, after eveything i did, the car would be fine for a few days to a week and then the fallen angel would come back to haunt the car again... sounds like hes a more permanent resident in your fox
  6. me and my dad figured it was just the ecu went bad after all that trouble... we didnt really care anymore though, just wanted the thing gone

    maybe you could swap yours out with a friends or a junkyard unit to see if that changes anything?
  7. Ye gods, I should hope it's not the ECM! Not that it's so hard to change, just tha it's a PITA to find and afford. Junkyard units make it kinda hard to find the exact match needed - it'd have to be a Mass-air 5-speed '89+ model, of which I've seen none at all in the local yards when looking for interior pieces - and I reeeeeeally don't feel like plunking down $150 or so on a new/reman'ed unit.

    No intentions of giving up the car at all ... although driving my '90 Town Car around yesterday made me start missing that '94 Crown Vic Interceptor I used to have. Ah, well ... guess I could always try washing the car down with Holy Water... :D
  8. Unless I misseed it I didn't see if you had tested / replaced your TFI Ignition module. Most of the autoparts stores say they can test them over the counter if you take it to them. Also I didn't see any mention of your O2 sensors. I know you said your codes were clear, but stranger things have happened. Just some thoughts.
  9. yea i didnt see a pick up coil mentioned either

    lots of others were replaced on mine that could solve your problem... keep in mind these weren't just random things we thought would work, my dads a level 5 mechanic for 30 years and each time he was sure this would solve the problem

    alternator, voltage regulator, pick up coil (whole dist. actually), cap, rotor, wires, plugs, tried making our own ground from block to frame to rule that out, grounded out lots of others, new battery, TFI module, coil, starter relay (different issue but still part of ignition)

    have you narrowed it down to a spark miss problem? or could it be fuel related?

    sounds like electrical DEFINITELY cuz of the intermittency of it all

    i really hope you solve ur problem without replacing ECU... ive heard 3.0 taurus comps work hehehehe
  10. O2 Sensors. And/or the harness. Run your codes and Ill guarantee that.

    I get the same thing with mine. SAME DAMN THING HAPPENS TO ME. Its a PITA. Im replacing my O2's and my harness this friday. So If it works Ill surely get back and let ya know.
  11. I've got some O2 sensors that are used (save everything cuz i'm a packrat) I'd gladly sent them to you so you can test that method b4 buying new ones.
    Good luck
  12. The ECM is a snap to change and not too expensive. Still, that would be a last resort. My guess would the MAP/BAP sensor and somebody already mentioned that. Take the TFI module to get checked out. You're almost out of stuff to check......
  13. hmm yea you might want to try a goose check too, wiggle every wire in the engine bay while the engine is running crappy to see if something clicks... then you can isolate a bad wiring connection, etc.
  14. I did the following (as well as everything above mentioned) replaced the MAP. The tab solenoids for the vacuum on the EGR equipment. New Distributor pickups , the usual Fuel pressure regulator. ETC ETC.

    O2's are last on my list.
    I have them on the way. As I already know my harness for them is shot.

    I was driving at night through some Uknown territory when I realized the the road was NO LONGER paved. My mustang bolted in the air as I flew over an Unpaved road with signs from the city stating " Unpaved Roads, City Not responsible for damage caused by these roads." Needless to say there were potholes the size of 460's EVERYWHERE>.. in one of these there was a piece or Rebar. Which snagged on my O2 harness ripping off the wiring for the driver side O2 sensor and for sure burning out the hidden fusible link in that line. So thats on my list. There on the way. And Ill will let you all know how it works on this weekend

  15. Well, the MAP/BAP/cRAP sensor didn't do the trick. Fifty bucks down the toilet. :(

    Not so sure about the TFI module. Usually when that goes out, the trend seems to be that it either results in a no-start condition when it gets hot (can only re-start when it cools off) or the ignition just craps out altogether while you're driving. I work at AutoZone, so I can give the module a test, anyhow, and see if that reveals anything.

    It's been to my understanding that 02 sensors very rarely cause drivability issues - they just eat up your gas mileage like crazy when they go. Right now, I'm getting 14 mpg going to/from work (less than 5 miles each way, I might as well get a bike) and 19 on the highway. Bear in mind this is with 4.10's, which aren't exactly economical. :D It's also not missing, at least not that I can tell, as I can hear it hitting on all 8 under acceleration, even when it's doing the herky-jerkies ... it's just surging. Idle quality changes just a tad for the worse when it's having its little moments of Dark Underlord influence, but otherwise all's good there.

    Just a random thought, could it be perhaps that my wimpy stock alternator could be causing this thing to chug and lurch as a result of the added strains I've placed upon it? I'm running a constant-on electrical radiator fan and a 200-watt Pioneer head unit, but otherwise everything electrical-wise is all original. The problem doesn't seem any worse/better with the lights on or off, but I figured it's a possibility, as I've seen failing/weak alternators cause some weird drivability issues in other vehicles.

    Mayhaps I should bolt a Bible under the hood...? :shrug:
  16. Check your PMs Dark
  17. May not have touched on this before, but the problem arises at any time, regardless of whether it's in closed or open loop mode (hot or cold). I'm going to reconnect my EGR spacer coolant lines, just for giggles, but the temperature issue doesn't seem to be a factor; it'll surge when I'm driving down the first street on the way to work, or it'll surge when I've already been out driving around for 15 minutes or so.

    The surging part is annoying enough, but the power loss is really a bugger. If I'm low in the RPM's and I try to gun it, I get little pops out the exhaust like it's running too rich and/or maybe not getting enough spark for whatever reason, even though it still doesn't feel like it's missing out. I've popped off the cap to take a look at that and the rotor, and even though they're both less than two months old, they're already pretty corroded - pretty disaapointing, considering they're brass terminals (AutoZone's "Gold Professional" cap/rotor kit). Gonna throw on a new Accel cap/rotor instead this Friday; might not change anything, but I don't like how things fuzzed up that much in such a short amount of time. Might also give the pickup coil a look, too, and see how much they cost ... although, doesn't that involve yanking the whole darn distributor out?

    Other things I've recently dabbled with:
    - Checked all 8 plugs, no unusual wear/fouling signs.
    - Wiggled, poked, prodded, and re-tied-up every little wiring harness, fuse, connector, sensor, etc. that I could get my grubby mitts on. Nothing is amiss. Even soldered and wrapped a couple of crimp connections, just in case it's a power drain issue. No change.
    - 02 sensor harnesses were a little oily from the throw-off from the small tranny leak, but even a dose of elec. contact cleaner and zip-tying them up and aside changed nothing.
    - Still running 89 octane, and my already anorexic wallet is begging me to stop paying $2.65 a gallon (gotta love Arizona gas prices). Dropping to 87 probably won't hurt anything at this point ... or will it?
    - No burn spots or dead plug wires, all getting proper continuity from end to end.
    - Swapped the ignition coil from the Lincoln into the 'Stang. No change ... except for girlfriend suspecting that I'm "poisoning" her car with parts from mine. :D

    The sooner I can stop putting money into Project Satanic Possession, the sooner I can finish the rest with a FRPP driveshaft (steel DS + 4.10's + weakening front U-joint = serious highway vibes), two proper rear tires, 3g alternator, and tightening up the steering situation. By then, spring of '06 shall arrive, and I can FINALLY hit the track; thereafter, I can commence to whine about crappy 60' and 1/4 mile times. :D
  18. Found three pinhole leaks in the exhaust. Slathered on meaty helpings of JB Weld. A little quieter inside the cabin at night, but still no change, otherwise.

    Things I have NOT replaced/tested:

    - EGR valve position sensor
    - EGR control solenoid (one of the three little vacuum-controlling doohickies in the passenger-rear corner)
    - Throttle position sensor (checked/adjusted, but haven't replaced)
    - primary ECM unit
    - ... and, again, I've already replaced the cap/rotor, but, to me, they already look like they're getting burnt up after two months. Anyone heard of a cap/rotor causing intermittent surging before?

    It also seems to come and go per each driving session. That is, I can start it up and drive around and it'll act all fussy with me, then I shut it off at a QT for a minute, restart, and I have no problems ... and then if I stop at yet another place, restart again, and the Prince of Darkness inhabits my motor yet again. Doesn't matter if I go two miles or twenty miles. Sometimes it runs perfectly from a cold start, sometimes from a hot start. If there were truly a pattern to these annoying moments of possession, I'd have more to go on. :shrug:

    I dare not bother taking this to a professional shop or a dealership, as they'll sit on it for weeks, pointing out every little irrelevant modification I've made to the car (Autometer gauges, A/C delete, etc.) and claiming it's responsible. (Y'all know how it is.)
  19. I like the Bible Idea. Also the terminology of 'doohickies'. Still sounds like an fuel or spark problem. How bout the fuel filter? replaced the cap n rotor lately i know you mentiond that. fuel relay? dare i say, fuel pump *gasp* clogged thingamajiggers? Let us know.
  20. Nope, fuel filter's new. Giving the cap/rotor a shot today. Seriously, I'm completely out of stuff to check/replace. The ignition module checks out fine, too.

    I keep thinking it's vacuum-related because it acts so similar to the way it did before I changed out the PCV valve and PCV screen; it would buck and pop and snort intermittently (although much worse than now), and as soon as I cleaned those out, the problem stayed away for a couple of months. I've replaced the PCV again, the screen is still perfectly clean, and the PCV grommet is new and seals up nicely, so that's all in the clear.

    The really weird part is, no matter how much I've searched the forums on here, I haven't found any similar issues that anyone else has experienced. All of the surging issues reported seem to be related to the EGR valve, and I've already replaced/cleaned that whole area ... well, 'cept for the aforementioned EGR valve position sensor, which may be next on my list of replacements.

    Perhaps the question should simply be this: In general, what causes intermittent surging and power loss? Maybe just a complete list of all possible factors. Then I can just go through the list and nail everything down.

    Sheesh ... almost 230k miles and I'm gonna wind up having an almost brand new car, if I keep replacing stuff at this rate... :nonono: