my question is how many rpm's is everybody getting for high idle from a cold start? i got a 1994 4x4 5.0L and it recently developed the habit of revving to about 2k rpms for a very short time then dropping back to 1500rpms, which i'm pretty sure is regular high idle. i have been getting the code for insufficient EGR flow off and on since i bought the truck which will be two years in may. thank's for any and all help.

oh i also got about 10mpg's last tank but i assumed that's from purely in town driving and making a series of short trips where it barely got to operating temp.

 

Yeah, mine hits 2k.

 

Mine used to go up to 2k then I solved a few vacum leaks now it high idles at 1500 rpm

 

Surges up to 1500-2k for maybe a second then drops to 1k, then as it warms up i have a slight stumble around 800 rpm then smooths out to 600-700 rpm

 

My EGR makes all sorts of noises when my truck starts, I can hear it gasping in there while the engine stumbles, then I guess when vacuum is sufficient, it straightens out.

 

ive replaced every vacum line and mine is still doing this ideas guys?

 

IAC?

 

wheres that at on these damn 4.9s?

 

I'm not sure, Probably on the throttle body somewhere so it bridged between the sides of the butterfly plates inside. about 5 inches long or so, cylindrical, electrical connection...

 

oh well ive cleaned all that within like the last 90miles i did all new vacum lines intake gasket valve covergasket at the same time and cleaned the butterflies with cleaner so i believe that shouldve gotten cleaned, are you saying that could be bad?