This is almost always caused by the Idle Control Valve (IAC), which is located near the firewall, on the passenger side, next to the throttle body. They sell for about $50. On generation 1 cars (1993 to 1996) these are very difficult to remove and install, but it can be done-or you could try to 'SEAFOAM" the intake by running a bottle in the gas tank and taking another bottle and run it through the intake by disconnecting the PVC hose while the engine is running, push the hose (it will suck the Seafoam into the intake) and then let it sit for about 10 minutes. Two bottles will run you about $14. When you start it up, expect alot of smoke-it might even bring the volunteer fire company, but it is the carbon build up being cleaned out of the engine. The engine should be fully warmed up before you do this. After you do this, disconnect the positive battery cable for about 10 minutes-it allows the computer (ECU) to 'relearn' inputs from the various sensors like the IAC. I actually did this on two Generation One marks I have owned, and in both cases, it cured the problem. The high idle in drive and park is tough on the engine and murder (in drive) on the already fragile transmission, not to mention the brutal effect it has on U-joints when you shift into drive at high RPM's, so you want to get it fixed as soon as possible or park it until you can solve it.
What is it?
In park, the transmission is in neutral: very little "load" on the engine. In drive, the engine is loaded somewhat by being in gear. Therefore, any engine performance issues will be exaggerated. Of coarse, engine performance issues could mean just about anything!
park,reverse,neutral,drive,low2,and low1
When we have this problem, we turn the ignition off and shift into neutral, restart the engine and it can then be shifted into drive or reverse.
The neutal safety switch will allow engine to start in park or neutral only. You must fix problem.
it is attached to the transmission and allows the engine to be started when the gear lever is in 'park' or 'neutral', but prevents the engine from being started in 'reverse' or 'drive'. on some cars the driver must also put their foot on the brake pedal before the engine can be started.
Park , Reverse , Neutral , Drive , Low
The engine also jumps when changing to Neutral and Drive. Should I have transmission fluid change? A/C was not on.
Drive cycle 1Start (car should be warmed up already)All electrical stuff off.Assure all diagnostic jumpers are off.Idle (in park or neutral)Rev engine to 2500 rpm(1.5L) or 2000rpm (1.8L) for at least 15sec.(in park or neutral)Rev engine to 4000 rpm for at least 15 sec.(in park or neutral)Idle for at least 20 sec.DoneDrive cycle 2Idle for 3 min.Accelerate to 55mph in 5th or D for 1 min.decel to stopDone
It will only allow you to start the engine in park or neutral.
Park and neutral
because in park or neutral the engine is free revving and when put in gear the engine is now turning internal transmission componets which puts a load on the engine