Car runs fine cold, stumbles hot

[AgentZ]

I gots a problem! its an 86 300zx. It will start fine and then run pretty nice until the engine warms up. Once it warms up it stumbles uneder 2000rpm like a..... I am a little lost on where to start.

 

This isnt a fun problem as this car is my daily driver at the moment and it is a little scary sometimes when you have to get off the line, also not a nice ride!

 

Any help would be great

[AgentZ]

Any ideas? I have a sneeky thought it might be the timing. would that cause issues such as this?

[Kevin Shasteen]

I'm afraid you're gonna have to do some more diagnostics before an answer can be given.

 

Your problem can be anything from a fuel sensor to a relay to the fuel pump to the fuel injection computer and its system.

 

All we know at this time is that your cold start systems are working properly.

 

Need to know:

 

Fuel Pressure on cold start/warm'd up engine?

Any noticeable fuel leaks in engine bay?

During the cold start can you rev your engine w/out hesitation or stumble?

When your engine stumbles is there any excessive smoke out the exhaust; if so what color is the smoke?

How soon does the engine begin acting up after start up and at what speed does the problem manifest.

Everytime the problem shows itself is it always the within the same time frame and same rpms?

 

Kevin,

(Yea,Still an Inliner)