Engine stumbling after start for couple minutes?

[helbigtw]

99 Solara 4cyl. 125k miles
History of this problem: After being parked at work each day, we had a cold spell, usually in the teens around 7pm when I would start the car. It cranked very slow and would not operate properly if I put it in reverse. My first diagnosis was to mess with the battery terminals and posts, clean everything up and make sure there were no electrical issues.

Now it cranks much better, but after sitting overnight or for along time in either cold or humid conditions, after starting the car, it runs fine, and runs itself up to about 1500 rpm, but, if I don't let the car sit and run for at least 2 or 3 mintues before putting it in reverse, or drive for that matter, the engine begins stumbling while in R or D, and even if I try to pull out from an intersection within say a minute of starting the car, sometimes I will hit the gas and the car lurches, hesitates...almost like its fuel starved.

I then changed the fuel filter..(which took all day due to rust and poor location). Now I've got solid battery connections, new fuel filter.

The engine is still stumbling a little bit if I put it in reverse shortly after starting the engine.

Keep in mind, in park or neutral, when the engine is essentially idling, there are no problems...only when the car is put into gear shortly after starting, does the engine start stalling/coughing.

My next step is to use this bottle of Lucas fuel treatment/cleaner to clean out the injectors in case the injectors are somewhat clogged from using 87 junk octane and having an old fuel filter.

I don't wanna start replacing a fuel pump or plug wires, that can get expensive.

Any other ideas? the spark plugs have about 30k on them and are "platinum plus"

[helbigtw]

bump

[desentrix]

Just a shot in the dark. Have you tried fuel injector cleaners, or using a bit of seafoam?

[gremlin70]

Hey helbigtw...have you found a fix to your problem?
My 2000 SLE v6 is doing the same.
When starting in the am and cold then shift to "D" or "R" the car begins to sound as if it's misfiring and shutters when giving it gas.

[gremlin70]

Not sure if you have the same problem I did. But finally after 3 dealerships looked at it and did not find a code, I was finally able to get someone to try swapping the coil packs 1-by-1. It was discovered that coil pack #2 was bad. So the hesitation that I felt was actually due to the engine misfiring.

So the CEL does not always light due to a bad coil pack... might be worth a shot for you if you take it to a dealer that has access to coil packs as they are expensive to play the swap game on your own.