93 Ford Taurus Sho hesitation

1993 Sho Tarus, 6 cy. hesitates when in idle. Mostly likely problem? Thanks for any help. :grinyes:

Welcome to the forum!

MTX or ATX? Have you checked anything (spark plugs, fuel filter, fuel pressure, plug wires)?

Also, can you elaborate on the "hesitates when in idle?" Does it stumble like a misfire? What does the tachometer do when it "hesitates?"

Has the car had a tune up recently? Have you tried a bottle of fuel injector cleaner in the tank?

Does it only "hesitate" when the engine is cold, or anytime the car is at idle? Runs fine as soon as you press on the accelerator?

Have you looked at the backside of the throttle plate and into the upper intake manifold, looking for carbon build-up? You may want to clean the Idle Air Control (IAC) servo as well.

-Rod

Ok, a little more specific. Car hesitates when warmed up and in idle. To keep running, you have to have the foot of the gas pedal. Additionally, there maybe the slightest smell of gas--running to rich perhaps. This is not a vehicle I am that familar with so that is why I am asking for help. Things that came to my mind was old fuel (probably would hesitate at the beginning not just after warming up), vacuum tube (probably not). Perhaps it does just need a tune up (but was told that it was done "not that long ago"). Clogged fuel filter (doubtful). Again, thanks for any help, and thanks for replying.

I would suggest checking the coolant temperature sensor to see if it might be telling the PCM that the car is cold, even when it's warmed up. There are two coolant temperature devices, a sensor for the PCM and a sender for the instrument panel guage. So, just because the guage seems to display accurately doesn't mean the PCM is getting an accurate reading.

Also, you could have an EGR valve that is not closing all the way. An open EGR valve at idle can cause the engine to stall.

If you turn the A/C on at warm idle with an ambient temperature above freezing, does the engine speed up? If not, you may have an Idle Speed Control servo that is acting up, but I would expect that to cause more of an issue when the engine is cold.

If it were my car, I'd start by adding a bottle of fuel injector cleaner to the tank and checking the condition of the spark plugs, plug wires, and vacuum hoses.

Also, just out of curiosity, you may want to monitor the battery voltage at cold idle as well as at warm idle.

-Rod