1992 fleetwood 4.9 idle problems
 

Hi I have a 1992 fleetwood that I bought a couple of days ago. It had a blown heater core when i bought it but that was a fairly easy replacement. When I first bought it it was running fine but when I had it running for longer than 10mins the the engine light would go on and the idle would dip down and jump up again. When it is doing this you can see the idle control valve trying to correct it or make it worse? I noticed the throttle body gasket is missing could that have anything to do with it or could it be the throttle control valve that is fualty? Please help

RE: 1992 fleetwood 4.9 idle problems
 

Gasket missing is not good, carbon built up can cause problems also. Codes?

RE: 1992 fleetwood 4.9 idle problems
 

Replace the gasket and report back.

RE: 1992 fleetwood 4.9 idle problems
 

I have replaced the gasket now and also adjusted the throttle control valve a bit . It is a little bit better but engine light is still on, I am still kind of new to the whole checking codes thing could you explain how you do it?

RE: 1992 fleetwood 4.9 idle problems
 

There are sticky's on this site on how to get codes but without a factory service manual, you have the bullets but no gun! The idle motor must be adjusted by the book, not just a guess.

RE: 1992 fleetwood 4.9 idle problems
 

Well yesterday i bought the service manual and i learned how to check the codes. The code that popped up was e25

e25 is EST Circuit Problem in Bypass Mode. This means the Electronic Spark Timing module is not operating properly. And bypass mode is a preset timing advance, programmed into the EST, and is triggered during cranking or low RPM (400). Above that, the spark is advanced based on inputs from various sensors, interpreted by the ECM.

ok ..

we got the codes, and one possible problem as defined by sven914

did we get the throttle intake cleaned?
idle motor adjusted by the book?