If you have problems with the car while it is in Park with the engine idling, etc. I'd address that first. With engine running in park, spray some wd 40 aroudn intake ports. Does the engine speed change? If so, I would then do a upper/lower inktake manifold cleaning with gasket replacement as listed in howto's.
If engine still won't run properly in park, I'd chek your plug wires. When did you last change the plugs? Also, check cam and crank sensor. Check throttle speed sensor. Check the ECT sensor - not the one for the temp gauge. The ECT temp is used by atx, computer, etc. Also check TSS.
Lots of sensors to check for sure......
Bob
