91 taurus is sick

when i first start car it runs great until i turn it off and when i restart it it just dont run smoth it feels like its missing sometimes the trans. shifts hard but let it sit for couple of hours and it will run like a charm until i stop and restart it please help guys my wife drives it and shes not happy

When's the last time you had a tune up performed on the car? Are the spark plugs and gaps good? Was the fuel filter recently replaced? Which engine does the car have? Have you checked fuel pressure, both KOEO and KOER? Any other details which could give us somewhere to start with our suggestions?

My initial guess would be a weak fuel pump, but without having any details, that's about the best I can provide.

-Rod

I agree with shorod, given what you have told us, it may be a weak fuel pump. My dad's Dodge Caravan had a similar problem. It would start right up and run perfectly, but if it sat for a while, it would take forever to start, and then it would run pretty weak until the fuel got up into the system. A new fuel pump fixed all of that.

But I can't say that is indeed the problem, as your post barely makes any sense, and I don't know what model of Taurus you have, what engine you have, nor any details of the problem.

it has a 3.8 it's been tuned up plugs ,dist. cap, wires about 2 mo. ago hoping that would fix it but it did'nt the fuel pump and filter was replaced in nov.07 when it died on my way to work.You let it sit about an hour it will run like a new car until you stop turn it off. And when you restart it thats when it starts acting crazy

Have you tried pulling diagnostic codes from the PCM? Do you regularly use fuel injector cleaner? If not, you should try both.

Also, the Engine Coolant Temperature (ECT) sensor could contribute to the symptoms you describe. Have you noticed a drop in fuel economy, and does the exhaust seem darker than typical?

Have there been any mods to the car such as a "chip" in place of the Intake Air Temperature (IAT) sensor?

-Rod

there are no codes and yes i use fuel inj. cleaner about every 3 mo. You said ECT sensor could cause these symptoms could that have anthing to with the way the air compressor clicks on and off ? because when you are driving with the ac or defrost on every time it cycles on and off you can feel the car kind of jerk?

Not likely. I don't think there's an input to the A/C system for engine temp. You probably have a low charge of refrigerant that's causing the cycling of the compressor.

-Rod