Ok bear with me this might be a little confusing so I will try and make this as clear as possible.

My car has been acting really wierd lately and here is the symptoms..
On start-up it mostly seems fine. Nothing at idle..idles smooth..no real issues.
drive it awhile and sometimes(not always) when I am cruising and let off the throttle to let it coast like going down a hill or something I don't need much throttle it surges sometimes and almost dies. I can put it in neutral and rev and sometimes it fixes it and I put it back in drive and everything is ok for awhile. Ok now..I cleaned the TB..the IAC..(seemed to help for awhile) Last night on the way home it did the same thing. Then it does die. Ok I pull off..turn key back then start it starts fine. Drive on...pull in the driveway it starts doing it..I put it in Park and let it idle..revs fine..when I let off it doesn't want to idle. Then dies again. Now it won't start at all. Cranks and Cranks...nothing. Would the IAC not allow the car to start if it goes bad? could it be the MAP? just give me some things to look at today. ECM? my opti is new..so is my plugs and wires..coil and I run the MS6AL and this problem started prior to that install. I know this sounds confusing but if you need me to clarify anything just let me know thanks....

Brad

 

Check the ignition control modual. I don't know if or how it can be tested though. Someone might chime in. Is the opti a true GM part or is it aftermarket? The IAC wont let the car start if it's closed, but if you crack the throttle it should start. If it starts like that, check the IAC. Get the specs for the resistances on both coils of the IAC and test them. You can also hook it up to a scanner and check the IAC counts (how far it is open) at idle.

 

brand new ICM..I have another ECM gonan swap that out today and see if that might be the problem..it isn't throwing any codes and that is what is another thing that is wierd...

 

maybe the coil??

 

oh fogot to mention the opti is a Gm part. swapping the coil today I had a blaster coil on it putting the stock on back on to see if that works.

 

wsn't the ECM..not the coil..the car actually started today but won't idle. Could it be the TPS or the IAC? doesn't miss or anything..might go up and down a few hundred rpms while holding the throttle steady..TPS??