2001 sunfire rough start

[brewsterbaker]

Hi all,

I have a 2001 4 door sunfire with the 2200 engine. It has 118000 miles. I bought it last springs and did all of the 100000 mile maintenance and then some. Plugs and wires, transmission oil and filter change, new timing chain, new serpantine belt tensioner, new water pump, antifreeze flush and replace, new valve cover gasket, new oil pan gasket. I have put about 5000 miles on it and it has run like a top. About a 1000 miles ago, it became difficult to start and would sputter around for about 15 seconds once I got it running. Then it would run fine. I also noticed that when I would pull out of the drive and take off with just partial throttle open, it would surge and slow down over and over for another 30 seconds. Then it runs fine. If the engine is warm it starts and runs fine. Any ideas? Some times it can be a real bear to start.

 

[melsg5]

Do you have a check engine light? Did you replace the fuel filter?

 

[brewsterbaker]

No check engine light. I would think if it was a dirty fuel filter that it would start ok, and idle fine, but be starved for gas under acceleration. What acts as a choke these days on a modern fuel injection car? That's what it acts like.

 

[melsg5]

A warm engine requires a leaner mixture than a cold engine, so if you have borderline low fuel pressure because of a partially clogged filter it will first become noticeable at startup. The choke function is controlled by the ECM and it's temperature sensors richening and leaning the mixture as required. I would also try a some fuel injector cleaner.