revving high??? and seems to be miss fireing at low rpms

[mikester1222]

ok i have a 91 honda civic dx auto dpfi some reason its revving high the throttle cable is lose not even tight. i just put a new idel control sensor in it because it was reving up and down finally quit that now its revving high. when i put it in gear it want to go by itself but i think its just from revving high. i also just changed the head gasket on it so could it be the timing is slightly off? i got new spark plugs and wires for it but seems to act as if it is miss fireing but no engine code comes up for missfire. can anyone help me out with these issues?
thanks
~MIKE~

 

[99sidude]

Sounds like you have a big vacuum leak somewhere. I'm not very familiar with the dpfi setups, but for obd1 motors, there are 2 idle control systems that can go bad. The IACV and the FITV.

 

[EFDX]

the up and down idle happens when the battery gets disconected, my dx has done it every time, sometimes it last for a few days, sometimes its gone after the first drive.
the high revving might be caused by a faulty or unpluged coolant temp sensor

 

[mikester1222]

It was none of these it was the intake gasket and to find out if that's your problem get some carb cleaner and spray it around the intake gasket while the car is running. If the idel changes and makes a diffrence you need to replace the intake gasket.