01 blazer zr2, 6 inch lift, 33s.
had an idle issue where it would drop and come back up over and over again. I think i started noticing it while i was driving as well. So today i got some throttle body/ carb cleaner and cleaned the TB. I just sprayed it a little with it still on the truck. NOW i have high rpms. 1200 about when in park/neutral. About 1000 when in drive or reverse. If I sit in DRIVE with foot on break and release brake, NO GAS I will get up to about 20-25 mph and like 3rd gear. I Unplugged the battery thinking that maybe the computer got thrown off because of the cleaning, NOPE! Didnt help at all. So Im thinking the TPS? But im not quite sure really. Please help me out. My last couple of posts for help went pretty much unnoticed

 

Id remove the tb and egr valve and clean them thoroughly

 

im thinking tps. Did the MAF sensor get hit with the cleaner?

 

I would say tps, I had a high idle about 1500 - 2000 rpms and it would go 40km/h with out gas. A new tps fixed it.

 

I actually had a maf code before and cleaned the maf with maf cleaner. I never got the code checked again, i dont want to buy a new maf unless its pretty obvious that its causing the problem. Theyre pretty expensive. But im wondering if its in a cold start mode or something because the maf is bad but it was just so gummed up in there that it didnt really effect it enough to do some crazy stuff. THIS BLAZER HAS HAD LITTLE TO NO GENERAL MAINTENANCE.

This weekend I will remove and clean the tb and egr valve + take a look at the maf, maybe that is the problem and ill get back to you guys. thanks for the help so far.

 

Well I took off the TB and cleaned it really good. Didnt help.
So I bought a TPS and put that in. Didnt help.
So since I had a MAF code I got a new one. Didnt help.

maybe ill go for the EGR tomorrow after I put in my 4wd actuator that went bad.

What else could it be if the EGR is fine?

 

Leaking vacuum lines?

 

i followed some of my vac lines today and found one the goes up by the dirvers side firewall and it was just taped at the end. but I couldnt find where it is supposed to go. I started it and covered and uncovered the end of the hose and the rpms would change but only by about 50. I need a vacuum line diagram or something to find out where its supposed to go.

as for the egr im not really sure. my Haynes manual says to take it to the dealer if im getting the egr system fault code(which i do have that code). And the egr only has a plug on it, no vac lines..

My rpms are still high and bouncing again like they used to, its colder tonight than it has been, im starting to think that the bouncing rpms have to do with the temperature outside?

 

Found out where the lose vac line goes. Into the reservoir in the drivers side fender. put it on but it didnt change anything.

Messed with the egr today, cut a piece of a pop can to fit the gasket and clog the holes to find out if it was stuck open or something and it didnt do anything, ran the same as before. I do have an EGR system fault code though but i dont wanna just buy a new egr for $150 unless i know its the problem. Cleaned it out and put it back on without the pop can. I cant completely rule the EGR out though since i still have the code.

Thoroughly cleaned the IAC as well today. Nothing seems to be helping.

Im thinking maybe I have some sort of leak on the intake manifold sucking air or the TB gasket? Im running out of ideas though. PLEASE HELP, any idea is worth a shot.

I also had an evap code P0452 i think it was. but i dont think that would cause a high idle, i think it jsut has to do with the fuel take pressure.

 

Did you try to move the IAC pintle when you removed it? I ran into a similar issue with my Jimmy and when I removed the old IAC I couldn't get the pintle to move no matter what I did. That includes putting it in a vise after putting in a new one. Couldn't get it to budge even after destroying it. However, the new one moved quite easily (though very slowly), with a gentle tug or push on it.