QuestionQUESTION: Hey Roland, my 3.5 LHS has recently been doing some funny stuff. sporadically maybe once a month for the past few months we would drive it somewhere ( like the store) get out go shopping then come back and it wouldn't start.... try it again.. same thing... then wait 10-15 minutes and it would start giving it some gas, and we'd be good to go again.
Recently we pulled out of our drive way, everything was normal, and started down the road. Started to come up to a stop sign let off the gas to coast a bit to it and the car just died. (Check oil light then came on)
I immediately turned off the key and tried to start it again, it had plenty of cranking power but would run. It wasnt until i gave it some gas while turning the key that it started. Then when it was running i went to switch it into drive and it quite again. So when i am not feeding it gas it just wont run.
I was able to start it and give it gas, then very quickly switch it into drive all the while still giving it gas. During the trip back to the house anytime i let off the gas for more than a fraction of a second the car again would quite and coast to a stop. As a side note the very night before this problem occured we were low on gas and i went and filled it up. then drove it back to the house with no problems. It ran perfectly fine until the next morning. ( not sure if its anything to do with gas, but want you to know all the story)
I was also told it may be my idle air control valve so i took it out and clean it... It had a lot of carbon black build-up on it. Put it all back together... It started fine and normal. I backed out the drive way put it in drive then made it about 100 ft then it died again. Any suggestions...
ANSWER: Hi Casey,
That behavior has all the earmarks of an egr valve that is sticking slightly ajar which leans out the mixture when starting or slowing to a stop, when it actually has to be closed tightly. It allow exhaust gas back into the intake which is the cause of the lean-out. You may have to remove the valve and clean out the passage way to allow the valve to close all the way. That valve earlier had an exposed valve stem which often could be corrected by merely spraying some WD-40 on the stem where it entered the body of the valve proper, but I am not sure that is still the case with the '99 egr. Take a close look around the base of the valve to find a rod with a slot in it which would be the valve stem if it is 'exposed'. If not, then removing the valve will be necessary.
I can copy the pages from the '04 manual CD and email them to you which shows how to take off the valve. But you need to tell me an email address which you can do by sending me a follow-up question using the 'private' option, otherwise the address won't show up.
You can also try a fault code readout using the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer window to see if the mileage reading changes to show instead a 4-digit number preceded by a P. Let me know the number if that occurs. We might get corroboration that the engine controller has detected a malfunctioning egr valve.
Roland
PS Please 'rate' my answer, and where you see the question about 'volunteer of the month' consider giving me a 'yes' answer. Thank you
Roland
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QUESTION: Also, what do i need to clean these parts out with? What is ok for use on the inside of the parts?
ANSWER: Any degreaser will do it, because it is all metal and designed to handle high temp exhaust fumes. I would avoid harsh chemicals on the vacuum part of the assembly however. Lube with WS-40
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QUESTION: Hey again, gave ya a great review, but now something else came up with the car. I had the throttle body cleaned out and its doing much better regarding the idle. Still not perfect the idle fluctuates some, revving up and down every now and again. We havent drove the car in a few days, but got in it this morning, pulled out and the check engine light came on. (It did seem to be doing fine, but i only drove about 100 ft then put it back in the driveway. Pulled the code P0123. my hope is that the TPS is just loose... any thoughts? Thanks!
AnswerHi Casey,
That code says the voltage on the TPS signal wire is too high suggesting either that the wire itself is shorted to a voltage source (5v or 12v) somewhere along the harness, or that the TPS is shorted internally. I would unplug the TPS and see what the wires show: pin 1 violet/white should show 5v, pin 2 orange/dark blue should show no voltage between it and pin 3 (it is the signal wire), and pin 3 black/light blue should measure continuity to pin 43 of the pcm as that is the sensor 'ground' wire. If those check out, then I would suspect a problem in the TPS. Try measuring the resistance between the middle pin and both of the outer pins as you move the throttle: they should show smooth variation of the resistance across the full range of motion, inversely to one another.
Roland
PS Thanks for the rating. You are entitled to do it again if you so choose.
