Interesting EGR valve problem - stumped - Page 2

nutjob · 07-23-2007, 04:23 PM

I think its safe to say that the ECM/PCM isn't the problem until all the sensors are checked for proper opeation. The intake air temperature sensor is similar to the engine coolant sensor so should measure that same resistance values against a published chart. The MAP sensor can be checked by simple substitution from another one, preferably from a junk yard one as it would be a coincidence for two faulty MAP sensors. The engine speed is the crank position sensor; any fault whether intermittent or complete will disable the engine. The CPS can be left out of this problem. The throttle position sensor may be tested by rapping against the TPS body with the butt handle of a screwdriver; if the engine immediately changes rpm then the TPS is faulty but this may not reveal itself to be contributing to the EGR valve fault. The vehicle speed sensor may show up as erratic needle fluctuations on the speedometer otherwise there may be no way to test this other than visually inspecting the sensor, unplugging it for measurement, and inspecting for broken/debris covered 'teeth' on the wheel hub.

insane_drummer · 07-24-2007, 04:36 PM

Thanks for the advice/help. I will do some digging and see i can't figure this thing out.

Joeybagodonuts · 08-03-2007, 11:25 PM

maybe i breezed through this thread to fast, but sounds like to me that you got a bad egr, yes, even if you bought a new one, ive seen literally hundreds of brand new parts bad out of the box, usallly its aftermarket parts, but sadly, latley weve been seeing factory motorcraft ford parts bad, like 5 bad cam sensors, weve had a lincoln a/c line from the factory that was built by good year and relabled a factory part, it fit like crap... but anywise, yes, id try another egr if the problem comes back when you plug the current egr in....where did you buy the new egr?

jimkana · 08-04-2007, 04:46 AM

I have a very similar issue... 1996 Saturn SL2 142,000 miles bucks and surges, downshiftsviolently, etc.. all during mid-throttle.
feather the gas and it is smooth, push it to the floor and it is smooth (but will not upshift!)
TPS Wires, Plugs, replaced.
Autozone checked the PCM, no codes.

Will an EGR cause this?
What else might caus ethis?
Did you resolve your issue?

insane_drummer · 08-11-2007, 04:09 AM

No i haven't resolved the issue. Due to lack of spare time, the car has been sitting. I think i'm going to try to check out some different sensors tomorrow.

BTW, I DID return the EGR valve to autozone for an exchange - the 2nd one caused the same problem - unplugged it as well, same results.

I'll try to post up what i find.

jimkana · 08-11-2007, 04:29 AM

I have fixed my issue!
I cut the catalytic converter off today and installed a test pipe.
WOW! What a difference.
My car runs like NEW!
I would not have beleived it if I hadn't experienced it myself.
One thing I hadn't mentioned that made me decide to try thr cat was the fact that my car had a crazy sounding rattle that I couldn't find.
Sounded like a heat shield but it wasn't, and when also it started up there was always this loud CLACK then the rattle.
The rattling seemed to come and go with RPMs as well so I was thinking flexplate or something in the tranny... But I called a local muffler shop I deal with and trust and asked the guy how to know if the cat was bad. The first words out of his mouth were "it usually rattles like a heatshield"...

So I took a chance and WOW!
I hope you fix your issue... You might want to get up under it and shake that cat around a little.. You never can tell.
Thanks for the response.
Jim

jimkana · 08-11-2007, 04:32 AM

PS: Before I did that I switched out the EGR and still had the problem. Then I literally plugged the EGR with a dime and the bucking went away but I still had real poor performance...
So I changed wires, plugs, tps, ects, cts, EGR, and finally the catalytic converter... It's always the last place yuo look...