ok i dont know what eles to do i have a 95 z28 it runs great cold but when it warms up it runs really bad cutting out missing all that but the really weird part it it will go away for the most part if you keep driving it i would say it take almost an hour thow i have also learned that when it starts running bad you can kill it start it right back up and it will run ok for maybe 5 to 10 mins

ok heres what i have tried
new coil
new wires
new opti not cap and roter thow
new icm
running with mass air unpluged
diff computer
checked the injectors
check for spark
new fuel filter

my opti plug is broke i have a new one on the way

if anyone can think of something im missing plez let me know
thanks

 

Unplug one of the O2s and see how it runs after warm up.

 

ok i unpluged the o2 and the car runs great so i guess ill replace the o2s

 

No so fast..that tests indicates that something is happening after the computer transitions from open loop to closed loop operation. In closed loop operation the car is looking to the sensors to set the running parameters. Pulling the O2 sensor wire just forces it to stay in open loop.

I would recommend you run a scan to find out what the computer is seeing from each sensor. You can download datamaster for free (for 20 times ) before buying it. All you'll need is a cable.

If I had to guess, I'd bet a whole nickel on this being caused by the coolant temperature sensor in the water pump. If the engine thinks it's cold it will run a richer than normal mixture which would give most of your symptoms..

 

How old are the O2s? They are considered "tune up" items and should be replaced on a regular basis.

You didn't say whether you had headers, but I've read that new headers that have not been run before putting the O2s in them, will destroy the O2s.

 

i did find that the temp sencor on the water pump has a bad pig tail and im goin to replace that right now as for the o2s i dont know how old they are i have somemore in my shop that im going to try

 

I replaced my O2 sensors a few weeks after doing my headers. I have read that 100K miles is a good place to replace them.

 

When ever you have an unknown and don't have a scanner, it's best to replace the item in question. At least the "tune up" items that is.

As far as headers are concerned. Whether they kill the O2s on first start up or not. I always recommend running them for a while with the O2s left out. Then install them later. Just good insurance against problems.