Hey Everyone... First post/thread in this forum.

I've been on automotiveforums.com for a little bit with a problem. They have been great helping me out.

I won't bore you with the minute details of this problem, but I have a very bad dead spot or stumbling problem when I am driving around very slowly or over speed bumps and such... basically anytime there is very little torque on the engine and then take my foot off the gas... it will start chocking and idling very badly almost as if it is going to die. It never does die all the way... but after a few seconds it just comes right back to normal and idles perfect.

No loss of power when I'm driving on the highway or just accelerate past the dead spot.

Now... I have gotten several suggestions that this is maybe an "air" problem. So I bought a new IAC and it didn't solve the problem....

Took the TBI off the engine and thuroughly cleaned it and the air passages... (it was very dirty.. lots of gunk and oil deposits... i'm sure carbon even had a chance to sneak in there somewhere)

This did improve the driveability a bit I feel, but I still have this problem with the stumbling.

Someone suggested the EGR valve... and I actually pushed the diaphram in while it was running and it made a VERY similar condition to the engine... so similar in fact that I believe it could be the very same problem.

My question is could this be the problem ... if it gets all gunked up... would it make the car cough and wheeze while going very slowly at say parking lot or driveway speeds?

I've had this problem for about a year... and I HATE IT!!!! I hate driving because of this... and avoid driving whenever I can... If this problem was gone... I would love my car. But after tuneups and TPS sensors... and IAC valves and blah blah blah... nothing seems to make it go away.

If anyone has a suggestion or can confirm this EGR valve thing... I will buy a new one.

If someone thinks its something else... please let me know....

Thank you all.

 

OMG!! I disconnected the tube coming from the EGR valve... and disconnected the power to the EGR selonoid... and for the first time in like almost 2 years... my car doesn't stumble when I go slow and take my foot off the break. This is AMAZING!!!

It still runs very rought... but at least it's running without the dead spot! So now my question is... what is wrong?? the selonoid or the egr valve?? How do I test each one??? Should I just plug up the vaccuum leak that i created and not hook up the EGR selonoid and valve???

Thanx for any help.

 

Sounds like you got a nasty vacuum leak somewere... especially if disconnecting and plugging those hoses helped your problem somewhat.

Check as many other vacuum hoses and related gaskets. If you have any doubts, replace them. Hose is cheap, so are most gaskets.

 

How long has it been since your car has a had a tune up? Did you clean your pvc valve as well. Those can get so gunked up that they no longer work or allow air to get through. You could have a bad spark plug wire or plug. Usually a vacuum leak will cause your car to idle pretty high without any serious stumbles. Have you changed the fule filter in awhile. At low engine loads a clogged fuel filter can cas a car to run wierd. At highway speeds it can suck enough fuel to keep the stumbles away. You could also have clogging injectors. Just a few things to consider. I would start by cleaning the pvc and changing the fuel filter.

 

Hey... Thanks for the advice. It has been awhile since I got a tune up. I just took the throttle body off and cleanded it out completely... got all the junk out of there... and cleaned the injectors... Put a new fuel filter on about a year ago... and I'm sure that it's still doing good. Hadn't checked the PVC valve... but the PVC passageway was REALLY junked up with oil and debris... I probably should check that for sure. Thanks for the advice.

Turns out the reason that my car was stumbling was the EGR valve... I just 100% disconnected it... and the stumbling went away... So now I need to figure out if it is my EGR valve that is messed up or the EGR selonoid...

Do you know of anyway to test these two components to tell which one is really at fault??

Thanx again for the advice.