1992 High idle in park and rough idle in gears

I have a 1992 ford explorer xlt. When i have it in park it runs at about 1500 rpm but when i put it in gear it drops to about 600 rpm. Then when i give it gas to go it starts chugging. I have also noticed a huuge loss in power. Any suggestions would be greatly appreciated.

Hi sounds like a vacuum leak,get a can of carb cleaner and spray the intake area also listen for hissing sound.engine running at idle,check for codes, is check engine light on while engine is running?
locate the mass air flow sensor with the engine off remove connector restart engine check if sympton is present.if not suspect sensor.

I can't hear any hissing and it definately isn't the mass air flow sensor or the throttle position sensor. I was wandering if an EGR valve could possibly cause the problem?

An EGR that is not closing completely is essentially a vacuum leak, but once the vehicle is moving that would have less of an impact typically. You complain of a lack of power.

How do you know it is definitely not a MAF issue?

-Rod

Hey is there black smoke from the tail pipe?

does the check engine lamp light illuminate when you turn the key to the run position
and go out when engine is running? if not Possible bad ECM

the fuel pressure should be checked? possible bad fuel pressure regulator.

you need to pull code/s with a obd 1 scan tool.

Verify the above sounds like its overfueling or a electronic control problem.

please give more symptons.

It isn't setting any check engine lights. When i pulled the maf sensor plug the car died immediatly however today a friend suggested the iac valve and i pulled the plug on it and nothing changed. it didn't affect the idle at all. Could this possibly be the problem and if so can i clean or would i have to replace the part?

The IAC is known to fail, but that should have no impact on the Explorer when it's running. It could impact your idle issues, but would not explain the huge loss of power when off idle.

-Rod

so do u think it would be worth it to pull it and try and clean the iac to see if that would atleast smooth out the idle??? As far as the loss of power from time to time while i am driving i can notice it has more power so it is inconsistant.

Okay, it won't hurt anything to pull the IAC and clean it and the passages in the throttle body for it. Be careful though not to lose or damage the gasket or the bolts when removing and reinstalling though. I've had very good luck with STP Throttle Body Cleaner for cleaning the IAC (as well as the throttle body). While you're in that area, you may as well clean the throttle body and as much of the intake as you can reach. Make sure not to let the straw from the cleaner launch into the upper intake though.

When's the last time your Explorer had a tune up? You might consider plugs and wires along with the fuel filter and air filter if it's been awhile. If you get the odd idle figured out you might try a can of SeaFoam in the "Cylinder Decarbonization" method. You'll probably be as amazed as I was in how effective that is.

-Rod