Ok, will do. I did plan on cleaning the iac valve and throttle with some carb cleaner but never did because the can says not recommended for fuel injection. I do have some crc contact cleaner I could use, what do you recommend?

 

Any choke or 2+2 cleaner should work for the EGR and IAC and throttle plate, but as far as the MAF I would use only a cleaner made for them I think CRC makes something for them. Be careful with the MAF, the resistors in them are very delicate.
That is great number for the fuel presure test, I am suprised it wasn't the regulator as your symptoms really lead me that way.

 

Disconnected the MAF sensor and did a test drive with no noticeable change in drivability. Also cleaned the iac valve and throttle plate afterwards, would have cleaned the egr valve too but my engine does not have one. Time will tell if it makes a difference. I will be sure to post as soon as I have any updates. Chances are if it doesn't make a difference I will know within a few days at the most.

 

I have a 02' blazer as well with a low idle ( 500 rpm ). Recently had heads rebuilt as right bank had low compression. I have installed new injectors, thoroughly cleaned IAC and throttle body as well as MAF, new cap, rotor, plugs and wires. Still have a low and rough idle. Looking for where to go next. Vehicle has 150K miles but well maintained. Any help would be appreciated.

 

Thought I would post an update, No stalls or hard starting in 2 days. I'm convinced my car has a little more power after cleaning the IAC and throttle body. My Blazer can and does go days or even weeks with no trouble but lately has been messing up several times a week, time will tell. I'll keep you both up to date on the status.

Beechbum, Nice attempt on hijacking my thread! Just Kidding. My Car usually idles right around 630 rpm and has a little shake at idle but nothing out of the ordinary. I have seen that as the normal idle on several other vehicles as well.

 

i rescently changed out my injectors,cause it was running real rich and giving off a bad smell.and running rough and it would want to stall at stop lights so id have to riv it up and put it on neutral.had problems starting it too.but i had fuel pressure i could here my pump.dont want to go through that again.

 

IT Technician-

Are you me? I'm having the EXACT same problem. I, however, have not yet tried as many fixes as yourself. I'm curious as to what you thought helped and what didn't? I have done the fuel pressure test and ruled that out(just under 60, down to about 57 after 10 minutes). After cleaning the throttle, IACV, and MAF I also felt like my idle was somewhat stronger, but it still dips when I put it into gear. Next up is probably replacing the PCV valve and hopefully smoke test my vacuum lines this weekend. Have you replaced the IACV? I'm guessing that's where'll I'll be at if the PCV and smoke test don't pan out.

Thanks-
Steve

 

It’s been nearly a week with no stalls or low idle, looks like cleaning the IAC and throttle body did the trick. If it happens again I’ll be sure to post about it. Thanks to all for your advice, I really do appreciate it. I did end up going a step further and removed the upper intake as well in order to clean in there a little. I uploaded some pictures for your enjoyment.
Blazer Forum - Chevy Blazer Forums - IT Technician's Album: Upper Intake

Steve02s10, Everything I did made no difference until I cleaned the throttle body and IAC valve. I plan on swapping the IAC valve for a known good one If I have any more problems. Don’t hesitate to replace your PCV valve even if you think it’s good, they only cost about 3 dollars.

 

Thanks for the quick reply IT Technician. Sure enough, replacing the PCV valve seems to have done the trick. It was pretty gunked up in there. I'm now getting a strong start and idle. Thanks for the pictures too, although that just makes me happier that the PCV worked, because what you did there looks a bit advanced for me.
And thanks to everyone providing support here, I would be completely lost if not for the trove of information on this website.

Steve

 

Well, Less than two weeks and my Blazer is right back to having the same problems again. Several times in the past few days I start it up and the idle drops real low and almost stalls. If I let it go and keep it running it corrects itself. Going to swap out the IAC valve and see how it goes.