Car: 91 z28 5.7 TPI coupe

I've got 3 problems that I'd like to fix:

1. When I start the car after it's been sitting for a while, I get puffs of white smoke.

2. When I start the car after it's been sitting for a while and then drive it through my parking lot, the car stutters as if I were tapping on the gas repeatedly. The longer the car sits, the longer it takes to go away. Like when I wake up and go to work in the morning, it takes about 800-1000 feet of driving. When I leave work (it's been sitting for 4.5 hours after lunch) it's gone in about 100 feet of driving.

3. Often when I've been driving and I'm stopped at a red light, my RPM pulse from what looks like 950-1000 instead of staying still.

Please help. Thanks.

 

bump

 

white smoke? head gasket? thats my guess. did it overheat? if it did i would do a compression test. if any of the cylinders are signficantly different than the others its probably a blown gasket. my stepfather once overheated a 350 in a 1 ton chevy van. we had to have the heads rebuilt and install new gaskets. have them checked for cracks at a machine shop.

 

#1 make sure it white or blue makes a big difference. Blue when first started then goes away= valve seals. White is usually coolant= not good

#2 try some good injector cleaner, your injectors migh be sticking

#3 see #2 fix that first then see what happens.

but of course fix #1 and the other 2 might be fixed also

 

1. How blue are we talking here? Is it something I could see myself in my mirror or should I have a friend start the car for me and look at it up close? They are just 2 quick puffs, one from each pipe.

2. Do you mean the stuff you add to your fuel that you can buy for like 5-10 bucks? Or actually opening up the engine and cleaning the injectors? If it's the additive, could you suggest a decent brand?

thanks

 

It would be a light blue, best to have someone outside look for the color, looking through the rear window makes it tough to tell since the windows have some tint. Since it is just a few puffs and then stops it is more than likely it would be valve seals.

I can't honestly tell you which one is better than the other, personally when I had the same problem on a Monte Carlo I ended up replacing the injectors. I haven't had much luck using anything after the injector is already sticking. Maybe someone else has better info as far as the additive.