95 f150 5.8 4x4 problem after mechanic

The idle in the truck was very high all the time. We took it to the mechaninc and they replaced the idle air control valve and the problem was still there. After that they replaced the ecm that was bad acording to them. Now, the idle has gone down but the problem now is that it dies. It starts and it dies. You have to rev it up for a couple of seconds so it wont turn off. Once it warms up the idle surges up and down between 1000 and below 500 rpm and eventually dies. Some times it could be fine but other it just crappy. The idle when in Drive is around 1000. Whats normal for this truck? Does anyone know what could cause the truck to stall? Is it possible that they mechanic replaced the ecm w/ a bad/wrong one? Another mechanic said it could be an intake gasket that was bad and thus the high idle. Anyone know how many types of ecm the 95 used?

We were thinking on getting another ecm but if we match it up to what we have, it will be the same problem if it is the wrong ecm to start with.

Any suggestions or thought are well appreciated!!

95 F150
5.8 4x4 140k miles E40D trans.

I would buy a can of carb. cleaner and spray along the edges of the intake manifold and around hoses. If you have an intake leak the engine will smooth out. I doubt it is your computer. I would really push your mechanic to fix it free I'm sure you paid twice for the same problem.

thanks! I will do the carb cleaner thing. I was thinking about taking it back but was too pissed to go back and them work on my truck again!

i had the same problem, it was the throttle positioning censor.

Quit throwing parts at it & do Error code scans! The ECU will probably tell you what the problem is. The "Mechanic" not doing it, tells me they're in it for the money only & milking the stiuation, or just plain stupid. ECU's don't fail that often. Warm idle should be 650-675 rpm. You can do a manual scanFord Fuel Injection » How To Run a Self-Test (http://fordfuelinjection.com/?p=13) or the easy way w/ digital numeric readout for $22.Equus Innova 3145 OBD-I Ford Scan Tool
(http://www.handsontools.com/Equus-Innova-3145-OBD-I-Ford-Scan-Tool_p_5574.html)