with the tps disconnected, is there supposed to be a change in engine sound? or maybe supposed to die?

Ive disconnected mine just for giggles and idle didnt increase not did engine die. ( i dont have a voltage tester, but tomorrow I will have a scan tool)

 

Xenon: Yes it could very well mean the IAC is sticky. The engine should not idle higher than 700 Rpm when warmed and in closed loop. The PCM doesnt want it to unless it cannot control air flow.. like with a vacuum leak, but you dont have a vacuum leak. or it wouldnt idle down till it dies.
SOMETIMES you can clean the IAC, usually it isnt worth it. Replace it. And then put the stop screw back where it was.

No... The TPS is used to set some baselines while cranking* but mainly for acceleration timing/fuel mixture/shift points. In a parked idle, it should not affect rpm.


* At WOT {above 4.5} reduce injector pulse-less gas; output changing while crank - increase injector timing - more gas.

 

Ok. Thanks for all the help! If it keeps up I will replace the IAC.

 

Decided to disconnect tps and start truck...idles high without it.

 

That's good to know.
See what I mean about setting 'baselines'?

Next thing to try in getting to know the system is warm it up to op. Disc tps while idle then goose it a couple times. I'm guessing the PCM will set a new baseline and probably idle at about 1000.

 

Well I've been driving the Blazer some. It still idles erratically... when I have the money I'm going to replace the IAC and I think that will solve it.

Really love this little truck... seems to do decent on fuel and is a blast to drive... Not bad looking either...