[Guest]

95 9C1:
The problem I have been having is after starting up, it seems like the engine is stubmling or missing. It goes away after a few minutes, or If I give it full throttle it won't do it.

AFter those few minutes it will run fine, then if I shut the car off and come back 20 minutes later or whenever, it will have the same symptoms for those first couple of minutes then return to normal running conditions.

Any suggestions?

 

[Guest]

-has the CEL come on?
-how's the idle when cold?
-have you ever cleaned EGR Valve, or installed a new one?
-have you inspected ALL your vacuum lines/elbows, especially PCV?
-have you insured all intake ducting clamps are tight?

 

[Guest]

-The engine light is not on.
-Idles at slightly higher rpm when cold, but not rough or anything
-EGR is blocked off and programmed out of pcm
-I'll have to double check on the vaccum lines and such
-Intake is secure

Someone mentioned to me that the fuel filter might be causing problems like this, but it seems like such a strange problem to me as it only exists for a couple of minutes after startup and goes away.

 

[Guest]

maybe someone that is capable of datalogging PCM, could find what's up?

Also make sure no wet gasoline is present @ vacuum elbow outlet, when you remove it from Fuel Pressure Regulator.

 

[Jim Curry]

95 9C1:
The problem I have been having is after starting up, it seems like the engine is stubmling or missing. It goes away after a few minutes, or If I give it full throttle it won't do it.

AFter those few minutes it will run fine, then if I shut the car off and come back 20 minutes later or whenever, it will have the same symptoms for those first couple of minutes then return to normal running conditions.

Any suggestions?

I have a 94 Impala SS, stock with cold air Intake. -125K miles, runs excellent except randomly after start up (usually 2nd start of the day) for a few minutes there is no power, stumbles and sometimes manifold backfires. I have changed plugs, wires, EGR, cleaned Throttle body, added air foil, cleaned MAF sensor, new fuel filter and a complete scan which showed nothing and no codes. The last thing I’m guessing to check would be the fuel pump as if I have time to let it idle a few moments it seems better.
any ideas?
I’ve been pursuing this site for a couple years now, since I was lucky enough to find a 94 bone stock SS, absolutely love it and has become my daily driver. This site is amazing with so much experience and knowledge, it’s very much appreciated.

Jim

 

[96 Black]

It isn't really 'throwing parts at it' as long as everything you've change so far on that quarter-century old bucket has been an original part. That way, it's just considered long overdue scheduled periodic maintenance, and perfectly called for since it sounds like you're not the original owner to know the history.

Things associated with changes of operation after coming up to temperature include ignition coil and ICModule which I don't see on your list, and you haven't mentioned the old 'shake TS outta every wire and harness you can find under the hood when hot' for loose connections, baked wiring and bad grounds. First things first and do the fuel pressure test most soonly.

 

[roy williams]

you have to replace the ignition coil and the ICM ... then the engine does not running then inspect the opti distributor ...
in todays world the CCP plastic is the cap and the rotor ... arcing of the plastic and the carbon ......I was in inspecting the opti cleaner ..