What would cause....

[steve1479]

A lopey Idle?? I've cleaned my IAC sensor just today. My car is a '89 Caprice Classic Brougham with the 5.0 V8 TBI. Everytime I start my car, I get a lopey idle that will continue until I put it in drive, only when warm though. I have had the car stall on me twice, once in Reverse and once when I put it in Drive. What could it be?!

[AdioSS]

all kinds of things. When was the fuel filter changed last? How old is the O2 sensor? Could the cats be clogged?

[mrcadillac]

my 96 caprice lopes alot at idle. But it has a bigger than stock cam in it. :P My car is loping a bit more than when I first got the car, and also stumbles at idle, and I plan on doing everything listed below on it. Atleast the stuff that applies to it.

Somethings I would replace would be Fuel filter, PVC valve, plugs(don't use champions). If the O2 is stock, I would replace that as well(don't use a bosch!)

Somethings I would check would be the EGR valve to make sure it isn't sticking, check the fuel pressure, clean out the cap and rotor making sure there's no mostuire in there. Clean the Throttle body bores, and plate, and the Idle control valve and passages. Use a tooth brush, and TB cleaner to get it cleaned up.


I was having this issue with my roadmaster. It idled rough, and stumbled just off idle. It also was a little down on power, but I didn't realize that till after I fixed the problem. The plugs, wires, coil, and O2's were already newer, so I ruled them out. Doesn't have cats, so I ruled them out. I cleaned the TB bores, and idle passage, and it idled smoother, but it still stumbled, and almost stalled a few times. I replaced the Fuel filter(which I couldn't even blow into and feel air coming out), and the stumble went away. It also gained alot of power, I would say 30hp judging by my 1/4 miles times of when it was plugged, and the neighbor hood of where it shoulda run.