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Discussion Starter · #1 ·
Last week, I noticed my car would shake during idle or while the car was in gear and at a stop. My usual routine is, turn on the car and warm it up to 1/8 temp., then drive off. My issues would usually begin after driving for a while and when the car would reach about 1/4-1/2 temp. on the gauge. I noticed the car doesn't have any issues during acceleration, driving or revving up the engine. The engine would visible shake and there would be hesitation at a stop or when I would slowly take off. If I tried to accelerate hard when the car was hesitating, there wouldn't be much power. The car felt like it wasn't getting enough gas, so I thought it would be best to change the fuel filter. Especially being that the car just hit 100k miles and unknown when the previous owner changed out the filter. After installing a new fuel filter and air filter, I continued getting the same problem. I also checked all my vacuum lines and hoses and everything appears to be intact. The Haynes manual stated that I might be having EGR problems or the coolant temp sensor might be bad. I've never owned a car with an EGR and don't have an idea where to look. What do you guys suggest?
 

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Maybe EGR, plug wires arcing, or even fuel psi. To check the EGR (its on the back of the intake manifold, kinda off center toward the drivers side, like a lil UFO). Remove the vacuum line from it, depress the diaphram and put your finger over the vacuum port and release the diaphram. If the diaphram dont hold open until you remove your finger, the valve is bad. Also open the hood with it running after dark to check for obvious plug wire arcing. Btw, have you had it scanned for codes? An EGR problem commonly causes a code. Get a fuel psi gauge too and see if it produces over 42psi at idle.
 

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I get this same problem when my opti gets wet after driving over a big puddle. I have been meaning to take it apart and add a thin bead of RTV to keep the moisture out, but have not had the time. How old is the opti?
 

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i am having these problem now. at first when i came back out from a door i always keep smelling gas. till one day i decided to look under the car and when i turn the car on (engine off) i quickly look under and i saw gas was drippin down somewhere. found out there was a broken seal ring.. got that replace. then the car start acting like you describe. i replace the gas cap and felt like it would go away but it was still there. with a fuel gauge my car idle at 36 psi.

try changing ur gas cap and check for gas leakage.
 

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Discussion Starter · #5 · (Edited)
94GoldPrice: My Opti-Spark is probably as old as my car and I doubt it has ever been changed. But I think I can rule the Opti-Spark out, I wash my engine every once in awhile and I usually don't have any issues. Also, I don't have any ignition break up under acceleration.

defdaboss: My gas cap looks pretty good with no wear on the ring. I also don't have any gas leaks. I just doublechecked everthing after I installed a new fuel filter.

DiGGM95: I don't have any codes. So I'm going to check the EGR and hope thats the problem.

Please let me know if you guys have any other suggestions. Thanks.
 

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Discussion Starter · #6 ·
I just installed the EGR and I continue to have the same issues. The old EGR was the factory part and looked in pretty good condition. The problems only occur when the car reaches normal operating temperature and still no codes. I checked all the vacuum lines, spark plug wires, injectors but I still haven't checked the fuel pressure. If I was having fuel pressure problems wouldn't I also be having issues under hard acceleration. Also, where is the fuel pressure port? Any other suggestions?
 

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Could be one or both O2 sensors going, or the ECT sensor is out of range. Sounds like something that only has to do with closed loop operation. Kinda taking shots in the dark.

Oh, just one other tip. When you start your car, only let it idle until oil pressure comes up and holds steady, then take off. Cold idling causes the most wear on your engine. Its better to drive gently until its warmed up.
 

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Iv been having the same problem, when i first start the car for the day it starts with no problem then the idle falls and you hear it start knocking then it idles up. Lately now that its cooler outside when im driving and i stop at a light the car almost stalls comes up then idles down real low, voltage drops real low, but if i turn the A/C on it idles fine. No hesitation during acceleration or reving engine.
 
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