My car still stumbles very bad when i have not driven it over night i need to push on the gas peddle for it to keep going after about 20 seconds it is fine and idles fine. I am stumped i almost want to take it to the mechanic but it is my daily driver and i dont have time for them to diagnose the problem etc. Any ideas?

Timing is good new plugs and wires i need to put my new dist cap on. O2 is brand new.

 

Do you think it could be a ICM

 

It could be, but I would check out the CSI. Make sure that it's getting power and that the circuit is complete.

The CSI is only active for the first few seconds of startup and running, so it very well could be inoperative, giving you the hard start and idle.

 

Does a 91 have a CSI?

 

The 3.1L engine does not have a cold start injector.

 

Opps...could still make sure that the IAT and CTS are reading correctly. I didn't notice that you had a 3.1. My Bad

 

whens the last time you reset the ecm? If you have recently, it may still be trying to relearn the idle.

Also an easy check is the tps.

 

Hmm it could be the TPS how would i check that? also i know on my car the tps can not be adjusted. I reset the ECM about 500 miles ago but when i have reset it in the past it has never done this.

 

Could be your MAP sensor is either reading a bad vacuum source or it's on its way out. This sounds like the same thing my MAF did before I replaced that (don't really know the difference between the MAP and MAF but they do a similar job). Check your vacuum lines, all of them, for leaks, especially the one leading to the MAP.

When you remove the vac hose from the MAP, if ANYTHING at all comes out of the vacuum nipple on the MAP, replace the MAP, NOW.

:edit: To check the TPS, you need a voltmeter. Plug the leads between the (green or blue, not sure as mine are quite discolored) ECM signal wire and the ground wire. Your TPS should read around .55VDC at idle.

 

Things that come to my mind....stuck EGR valve. Will give the car a poor idle when cold, once it warms up it will improve slightly but still not be completely steady, makes it sound lopey.

Also, leaking fuel injectors. But this is more of a hot start issue....overnight the fuel should evaporate enough to not really cause an issue.

Does it smoke on startup? Possible bad valveseals could cause oil leakdown into the cylinders/spark plugs and cause hard starts and poor engine behavior til the plugs clear themselves up.