My 99 LS automatic 2wd starts and idles perfect every morning and I usually let it warm up a little before I go. After I start moving down the road for about the first 10 minutes it acts like it's missing (intermittent slugishness) at any speed and through all gears. Once it warms up to normal operating temp, it straightens out and runs fine. It will occaisonally throw the random misfire code but then usually the Service Engine light goes away after a short time. I think this may be a sensor issue but not sure which one. If anyone has seen this before and figured it out I would appreciate any info.

 

I would run a can of seafoam through your gas system.
Your engine should have 2 fuel injectors, one for cold starts/ideling, and the other for all other times. If the seafoam doesnt fix the problem you may need a tune up. When was the last time you did a tune up? When was the last time you replaced the fuel filter? Thats were I would start.

 

I've only had it for about a month so It's probably due for a tune up. I sure didn't know that it had an injector just for idle and cold start. I've heard good things about the Seafoam we'll give it a try. Otherwise, it'll be tune-up time. Thaks for the reply.