420A 2gNT stumbling when first started

[98primeredrs]

Whenever I first start my eclipse it cranks and a couple of times and then will stumble to get up to idle then jump to the regular idle rpm. Any ideas on why it would be doing this. The car has never done this before and idles fine after it jumps to the normal idle rpm. I changed the rubber engine mounts to the polyurethane insert ones and it started doing this idk if that would cause this issue but im just throwing it out there incase. The car has a 420a and a 5 speed. Any help will be appreciated.

 

[pauleyman]

did it just start this or has it been doing it awhile? Check engine light? Any new repairs?

 

[98primeredrs]

did it just start this or has it been doing it awhile? Check engine light? Any new repairs?

just started after doing the mount inserts. I also changed the valve cover with one I painted a different color but i checked the coil and plug wires were connected. no check engine lights either.

 

[BLACK'98DSM]

Try holding the throttle slightly open while starting it. If that seems to help then your intake manifold and throttle body might be clogged with a crud buildup from the EGR and PCV valve. Or perhaps the IAC valve is not self adjusting for a cold start (should contract allowing more airflow thus higher idle).

 

[98primeredrs]

Try holding the throttle slightly open while starting it. If that seems to help then your intake manifold and throttle body might be clogged with a crud buildup from the EGR and PCV valve. Or perhaps the IAC valve is not self adjusting for a cold start (should contract allowing more airflow thus higher idle).

I held the throttle open maybe 15-20% while starting it and it didn't help at all. I went and unplugged the IAC valve and it revved up so I'm going to assume that the IAC is working as it should. I turned it off once it up to temp and turn it on right after and it started normal without any issues. The only thing I could of is the IAT sensor might not be working completely right idk I'm stumped with this issue.

 

[pauleyman]

I held the throttle open maybe 15-20% while starting it and it didn't help at all. I went and unplugged the IAC valve and it revved up so I'm going to assume that the IAC is working as it should. I turned it off once it up to temp and turn it on right after and it started normal without any issues. The only thing I could of is the IAT sensor might not be working completely right idk I'm stumped with this issue.

starting normal right after shutdown to me points to fuel pressure leaking down or a leaky injector. I don't know how 420a prime but if you can prime the fuel pump before startup you could mostly rule out fuel pressure leakdown. Leaky injector let the car sit overnight and then pull the plugs. If you have a leaky injector that cylinder will smell strongly of fuel. The car will stumble for a few seconds at cold startup trying to get rid of the excess fuel then it smooths out and no issues until the next time it sits.

 

[BLACK'98DSM]

Turning the ignition switch to the ON position primes the fuel pump for 2 seconds.

 

[98primeredrs]

starting normal right after shutdown to me points to fuel pressure leaking down or a leaky injector. I don't know how 420a prime but if you can prime the fuel pump before startup you could mostly rule out fuel pressure leakdown. Leaky injector let the car sit overnight and then pull the plugs. If you have a leaky injector that cylinder will smell strongly of fuel. The car will stumble for a few seconds at cold startup trying to get rid of the excess fuel then it smooths out and no issues until the next time it sits.

I see what you are saying. ill give it a try tomorrow after work.