I posted this problem in the mustang forums and I cant seem to get a straight answer so I thot I would try putting it here because the people at this forum seem to be more intelligent.

I recently bought a 94 mustang convertible with a 3.8 v6 and an automatic tranny. I got the car cheap because the head gasket was blown. I got it to the house and removed the heads. when i removed the exhaust manifolds the pupes were left open, and when the head was removed some antifreeze got into the pipes. anywho, i got the heads re-done and got the new gasket set and so on. i get everything put back together and i start it up and it runs really bad. it wont idle worth a crap and it smokes really badly. the smoke is white so im guessing its the antifreeze that was left in the pipes burning off the cat. sntifreeze also drippes out the tail pipe. anyways, when its running, i hit the accelerator and the rpm doesnt increase untill i let off the throttle. its like the rpm's increase only after the throttle blade closes. i am running the motorcraft plugs and motorcraft wires. I am at a loss here and i need some help. while i had the upper plenum off i removed the throttle body, IAC and EGR and cleaned them throughly and sealed them up with new gaskets. if there are any test i can run or any suggestions at all please let me know.

thanks
josh

 

Any chance you got it too cheap ? Like, is the intake cracked and bleeding coolant into the combustion chambers ? Pull the plugs and see which ones are wet of coolant. Have a leak-down or compression test done at the same time, in case your head gaskets got botched. Did it run like crap before you pulled the heads ? Are the heads cracked too ? All things to check.

 

Could be the fireing order, you must have mix matched the plug wires when you put them back on. My brother-in-law did that when he put headers on his tahoe. Sounds like the same symptoms. The Fireing order should be listed somewhere in the engine bay, if not its def. in the manuel.