gmbellew
Full Access Member
- Joined
- May 27, 2018
- Posts
- 1,239
- Reaction score
- 1,327
- Location
- Kansas city
- First Name
- glen
- Truck Year
- 1990
- Truck Model
- suburban 1500
- Engine Size
- 350
idle will always jump when you return to park bc the load comes off the engine. it could jump to maybe as high as 950-1000rpm. but should settle down fairly quickly and likely be in the 750rpm range fully warmed on a stock computer chip. in gear idle will be in the 525rpm range, also stock chip. IAC should be 5-30 in gear stock chip. and in park should be close to that IAC range also. all those are for fully warmed up and ac off.Just went for a drive and it warmed up and switched to closed loop. With the IAC unplugged it idles like it should. Once it was warmed up it would idle at 1000 rpm in drive completely stopped. When I shifted it into park, it started idling at 1450 rpm and slowly went back down
does TPS return to "idle" voltage quickly or does it hang? could be a linkage issue if it returns to idle rpm slowly after revving?
your IAC counts didn't go to 0, did they, with 1000rpm in gear warmed up? bc it really sounds like some sort of vacuum leak...
edit - those coolant temps are too low. you should have a 195deg thermostat in there. cold coolant temps will mean more fuel and a higher idle....I'd be looking at the temp sensor itself or the thermostat to make sure it isn't stuck open.