My car idols fine, Drives fine, but when im going at a steady speed and give the throttle a little gas it starts to stutter and sometimes the rpms seem to wind up too high before it actually shifts and sometimes ill drive for awhile shut the car off then try to start it again and doesnt start, the D4 light flashes, so i repeat turning the key on and off until the D4 light stops, then the car starts. ive done a transmission flush, complete tune up including coil, fuel fitler, and it hasnt helped the promblem. please help me
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I had the same problem with mine! I spent what seemed like hours trying to figure it out. I finally gave up and just said, while I'm here I'll just do all my preventative maintenance checks and give up for now. I noticed while checking the radiator that the antifreeze was low so I added a little less than a couple of quarts, closed the hood, started it to move it back to the driveway and guess what? It fixed itself! I guess it was just low enough on fluid it was telling itself, "I need to warm up." Hey, maybe you'll get lucky and the same simple thing might be the problem. Also their is a (usually vac. controlled) switch located on the throttle linkage that allows your engine to de-accelerate "softer" instead of just dropping all at once when you let off the gas. I have seen these switches with age or dirt and grime, stick in a position that the throttle wont fall all the way down. A couple of things to check that my be a simple fix. Hope all works out for you!
If the car starts to hesitate at right around 2000 to 2300 RPMs then the EGR ports on the intake manifold need to be cleaned out. The exhaust gas is flooding only one cylinder and causing the hesitation(misfire of that flooded cylinder) since all the other ports are blocked off with carbon build-up. This happen right when the EGR valve opens, letting in the exhaust gas. To find out if this is indeed your problem, remove and plug up the rubber vacuum hose going into the EGR valve and drive the car. If it stops hesitating, that's the problem.
try unplugging the egr vacuum source and plug the line and drive. If no difference you ruled out the egr as being the issue.
Please do not rate this solution since by not seeing the car and doing my own test there is no way to tell if maybe you just hooked up something wrong.
idle air speed control valve(iac),too low idle or driveline problem like play in the drive shafts. if you put it in park and give it to say2500 rpm and let go of the throttle,does it return to 900rpm?if it dips down to 5 or 600 then to 900 the iac is bad.
Or it might be defective. See steps below to check...
Disconnect idle control solenoid valve electrical connector.
Disconnect upper hose to solenoid valve from manifold and apply vacuum to hose. Valve should hold vacuum.
Continue applying vacuum to hose and briefly energize valve by
connecting battery positive terminal to the black/yellow wire terminal
and negative battery terminal to the green/black wire terminal. Valve
should not hold vacuum when energized.
If idle control solenoid valve fails to perform as outlined, valve is defective.
YOU CAN TEST IT WITH A OHM"s meter or a multi meter one is your ground wire the other two send the signal to your computer.what you are looking for is when you rotate the throttle do it as slow as possible and as steady.If the reading jumps alot when you slowly rotate the throttle then it is a bad tps.let me know what the outcome is.Thank you for using fixya
If your car is fuel injected it may be the throttle position sensor, (TPS) hook up a DVOM and check that voltage output of sensor is steady closed to open throttle, since 35MPH is near closed throttle, that is were to focus your attention, also the mass air flow meter (MAF) may be at fault, do you have any codes? These 2 parts donot as a rule set codes.