What else could cause a care to idle rough?

Question

I have a 1997 Plymouth Neon. When I come to a complete stop the RPMs go down to 500 then most of the time it stutters then goes back up to 1000 RPMs. Sometimes it will die. If I give it gas while in park it helps it go back up or not stop. IT DOES NOT STALL ALL THE TIME. I had a tune up done to it, O2 sensor replaced, an oil leak fixed, and a fuel injection clean up done already. But it still doing this??? Anyone have any other ideas what could be causing it to idle rough????

Answer 1

Sounds like yes, it could be a vacuum leak, or more likely an EGR valve thats stuck open.

Answer 2

Sounds like you have too much fuel from a leaky pressure regulator. WHen you hold on the gas you are introducing more air into the system to help make your air fuel ratio more correct and keep your car running but the more air and fuel makes it idle higher. Hook up a fuel pressure gauge and see if you pressure is in spec and see of pressure holds or drops off rapidly from the regulator leaking.

Answer 3

i'd desire to declare a foul O2 sensor as nicely. 80 4's fairly have been given right here with the Iron Duke 4cylinder. What happens is as quickly as you first initiate the motor vehicle, this is going to run in open loop, till at last the oxygen sensor is heat sufficient to catalyze the exhaust gas to grant a maximum suitable analyzing. on a similar time as in open loop, the motor vehicle will run on the Coolant temp sensor to grant precise gas. as rapidly via fact the motor vehicle warms up, then this is going to bypass into closed loop, which the motor vehicle calculates gas combination via making use of the O2 sensor somewhat lots thoroughly. in case you have a foul O2 sensor, you will get driveability issues on a similar time as the motor vehicle is going into closed loop. If the provider Engine rapidly basic is on, take the cig lighter trim plate off to earnings get entry to to the ALDL diagnostic port, and stick a paper clip between pins A and B with the significant in run, although the engine now no longer working. you will get code 12 three times. that's hassle-free. Then, the computing device will flash the various codes that have been set three times each. in case you gat a code 40 4, then the O2 sensor is showing a lean subject. Code 40 5 potential a rich subject. Code 13 potential that the O2 sensor circuit is open (shrink cord, or undesirable 0.45V reference indoors the ecm.) So, to summarize, in case you get a code 13 (now no longer in all probability), 40 4, or 40 5, then i'd desire to be looking at a sparkling O2 sensor, or fixing the cord. want this helps.

Answer 4

Try a self diagnostic on it. Turn ignition switch on/off 3 times w/out starting vehicle. On the last time leave in the "on" position(remember-don't start vehicle just turn it on) look at the light that says "engine". It should start blinking a certain sequence try to write these down. Contact local dealer/auto parts super store and see if they can decipher the code for you. Good-luck.

Answer 5

A faulty mass airflow sensor can make the engine seem like you have a bad fuel pump.

Answer 6

I would check for a vacuum leak first. If vacuum is normal then I'd check out the idle solenoid.

Answer 7

could be an idle air control on the throttle body or a throttle positoin sensor

Answer 8

sounds lie a vacuum leak

Answer 9

fuel distributor??? different than fuel pump.