I have a 1990 k3500 with the 454 in it and the thing idles at about 1200 and stays about that when i put it into drive but it drops alittle. After getting it warmed up I poped the hood and pulled the oil dipstick alittle bit and this foggy smoke started to come out and i was just wondering what internal is shot?

 

how many miles are on it and it sounds like you may have a vacuum leak on it and smoke coming out is not really normal but its not really bad type thing. i work at a GM dealership and when i do oil changes and am pumping oil in the motor smoke comes out when the motor is hot when it comes in for an oil change, i think its not something to worry about but then again if it has some miles on it you prolly have a blow by problem valve stem seals where bad on those years they where not designed very well i have that problem with my 88 and it had 81 000 on it when i bought it

 

apparently 65k from the guy i bought it from but im thinking 165k

 

High mileage or not, the smoke your seeing when you pull the oil cap isn't a major concern. The idle issue is acting similar to a stuck choke. On startup, it revs higher till it reaches running temp, why it's not throttling back makes me think a sensor or vaccuum issue.

 

What would be a proper compression reading for my engine when i put a compression tester on it? and also what sensors on the throttle body could be making it idle high for awhile till it is warm and also is there anything that can be adjusted?

 

Tps can do it, Iac can as well. If I remember right 120-135 on compression but don't quote me, it's been a while since I've looked at those stats.

 

Yep, I wa wrong.... 150 is the magic number.

 

Should i change the IAC or the TPS first? and another question i thought of today is am i able to take the dually tires and rims off of my axle and put regular single wheeled rims on it?

 

disconnect your iac wiring from the tbi then drive it around the block if it runs better with it disconected then replace it
a bad temp sensor will also cause that to happen
disconect the one at the top of the engine and see if it runs better youll know its bad if it does run better without it
then try the same thing with the one on the side of the engine next to your number 1 cylinder exsaust manifold outlet

 

all of my compression readings were 125-132 PSI.. Is that decent enough? and i did unplug that and it didn't do a whole lot and it is still idling at like 1200 RPM and then dropping down after it gets half way to operating temp.