I have an 03 GT automatic while driving and when its in over drive it surges @ 35-40 and @45-50. When i take it out of over drive it still does it just not as bad. The things i have done are new ford coils, factory plugs, factory fuel filter, lucas injector clean, and EGR vaccum silenoid. Before i did the EGR vaccum silenoid i plug the vaccum hose that goes from the EGR vaccum silenoid to the ERG valve on the drive side intake. It seemed to clear it up alot. So, thats why put a new ERG vaccum silenoid on it but, it still did the same thing so i plugged the vaccum hose up again still does a little bit. Can anyone help me.
surging
- Thread starter kreil45
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wmburns
SN Certified Technician
I'm assuming there are no DTC codes are you would have posted the full codes (right?).
If removing and pluging the EGR vacuum line improves the symptom "alot", that implies excessive EGR flow. This also tends to indicate that the EGR value itself is closing or mostly closing.
However, the fact it does not improve it 100% may mean that the EGR value is not closing fully. Or there is an additional problem/cause.
Also consider that a vacuum leak can play a part in this problem. Change the PCV valve. What about the condition of the all vacuum hoses?
Why did you change the EGR solenoid? That is a rare part to fail.
Focus instead on the DPFE sensor. Exhaust gases are hard on these parts. Check the vacuum lines to/from the DPFE sensor. These must be leak free.
Check the electrical connections to the DPFE sensor. Are they clean and tight?
If high mileage and you can't find a hard fault, consider replacing the DPFE sensor. It fails about as often as the EGR valve itself. But, in your case, I would replace the EGR valve first.
If removing and pluging the EGR vacuum line improves the symptom "alot", that implies excessive EGR flow. This also tends to indicate that the EGR value itself is closing or mostly closing.
However, the fact it does not improve it 100% may mean that the EGR value is not closing fully. Or there is an additional problem/cause.
Also consider that a vacuum leak can play a part in this problem. Change the PCV valve. What about the condition of the all vacuum hoses?
Why did you change the EGR solenoid? That is a rare part to fail.
Focus instead on the DPFE sensor. Exhaust gases are hard on these parts. Check the vacuum lines to/from the DPFE sensor. These must be leak free.
Check the electrical connections to the DPFE sensor. Are they clean and tight?
If high mileage and you can't find a hard fault, consider replacing the DPFE sensor. It fails about as often as the EGR valve itself. But, in your case, I would replace the EGR valve first.
wmburns
SN Certified Technician
DPFE-Differential Pressure Feedback Exhaust Gas Recirculation (EGR) System
Look for two vacuum lines coming from the EGR pipe. The DPFE sensor is at the end of those lines.
If no DTC codes, focus on the EGR valve not closing fully and a possible vacuum leak before replacing the DPFE.
Did you clean the MAF?
Not a bad idea to have the alternator tested for correct output and excessive AC ripple. Most autoparts stores will do it for free.
Look for two vacuum lines coming from the EGR pipe. The DPFE sensor is at the end of those lines.
If no DTC codes, focus on the EGR valve not closing fully and a possible vacuum leak before replacing the DPFE.
Did you clean the MAF?
Not a bad idea to have the alternator tested for correct output and excessive AC ripple. Most autoparts stores will do it for free.
wmburns
SN Certified Technician
A basic function test is to apply a hand vacuum at idle. If the motor begins to run like crap, the EGR is flowing. Remove the vacuum and the motor returns to normal, the EGR valve closed.
Note, if the EGR valve is not closing fully, the basic functionality test will not pick this up.
Note, if the EGR valve is not closing fully, the basic functionality test will not pick this up.
Stumbaugh
Member
Mine was doing the exact same thing here recently. I deleted my EGR and cleaned my MAF and it has 100% went away.
O.K. after testing today i have found nothing out. Thing that are done. It has a new EGR vacuum silenoid and a new EGR valve. I tested the old EGR and it was dropping vacuum a little bit so i replaced it, nothing. Removed the vacuum from the EGR vacuum silenoid and one of the hose was sucking so thats good. Check the volts on DPFE and they were good and check the volts on the EGR vacuum silenoid and that was good but it still surges while its at 35-40 and 45- 50 and when i plug the tube coming from the EGR vacuum silenoid to the EGR valve it runs alot better not perfect but better. 
what else is there beside gas and match.
Oh yea and I also replaced the air filter and cleaned the MAF
what else is there beside gas and match. Oh yea and I also replaced the air filter and cleaned the MAF
Stumbaugh
Member
On the side of the plenum, there is the EGR valve that has a metal hose that routes down to the exhaust manifold. Unscrew the nut that holds it to the manifold, and remove the valve from the side of the plenum. Remove the whole assembly. There is also a sensor that is attached to all of that stuff, unplug it and remove it also. There is also a vacuum line that plugs into the top of the EGR valve, cap off the vacuum line. You also need to cap off the spot on the manifold where the EGR tube ran into. I took the metal tube and cut it, leaving about 2" sticking outside of the nut, then I welded it shut and screwed it back onto the manifold.
It might have taken 30 minutes total to do. You will need to turn off your EGR on your hand held, or if you have a tuner, have him shut it off. If you dont, it will throw a code.
wmburns
SN Certified Technician
FWIIW, the dropping RPM isn't likely to be EGR. Why? Because the power output of the motor would drastically be affected if EGR were flowing at that low of RPM's. Besides, what would keep the motor from just quiting? IE, why the recovery and then apparent normal operation.
IMO, it's more likely that either the automatic lock up torque converter is not releasing as it should or the IAC isn't responding as it should.
How to tell. If the RPM's drop only happens when coming to a stop, then it's the transmission. Have you checked the condition of the fluid?
If this is a common garden variety idle/IAC issue, then it won't make a difference if the car is in neutral. IE, the RPM's will drop even in neutral.
The EGR system isn't going to have any effect on the cruise control. That's just reaching.
Stumbaugh
Member
Well, that isnt the EGR system. Sounds like you either have a vacuum leak, or a bad IAC. The cruise control problem is more than likely something electrical, maybe a fuse or something.
Also, you could have a dirty MAF. Go buy some MAF cleaner and clean yours then see what it does.
The surging could also be a fuel filter, spark plugs, or a number of things. When was the last time you performed a tune up on the car?
I just cleaned the maf as well. I was going to replace the spark plugs next weekend anyway so ill get a fuel filter too and replace that and see what happens. I want to delete the egr anyway just to clean up under the hood a little bit. How did you plug the vacuum line? Did you get rid of the egr solenoid or dpfe or do those stay?
Stumbaugh
Member
Follow the vacuum line all the way over to the passenger side. Cut it right before it merges with anothr vacuum line. Take a lighter, heat up the end of it, and smash the 2 ends together. They will melt together and be just fine after that.
Remove EVERYTHING that has to do with the EGR.
O.k. here is what i found out. I broke down and took it to the dealership. What they told me, i never would have guest. Even though i had no check engine light or over heating problem they said there was a code. It was my thermastat was sticking open and the computer thought it needed more fuel when it didnt and fuel washed the plugs. So, i changed the thermastat and put in new plugs and problem solved. Wish i would taken it to the dealer to begin with. So, i hope this helps anyone.
this sounds like what mine is doing right now. i have a 92 gt, i have the maf unplugged right now cause it has a rough idle.. i was thinking of putting in a new coolant temp sensor and thermostat..i was told it could be causeing it to starve for gas or flood to much.. was your them bad or just not working all the time.
i have pu ton new idleair,maf,tps,, and just stumped...replaced fuel filter and doing trans fluid/filter tonight when i get home..
i have pu ton new idleair,maf,tps,, and just stumped...replaced fuel filter and doing trans fluid/filter tonight when i get home..
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