For awhile now, my 2002 Blazer (2dr LS 4wd) has been intermittently stalling. What happens, is that I'll come out to start it, and it will start then shut off right away. I'll have to start it and rev it to around 500-700 RPM, and it will stay running. I'll have to keep it at that RPM as I pull out of my driveway, and it will sometimes last the entire way to work (about 5 miles), because if I stop at a light, and if I don't keep the RPM's up above 500, it will stall. This does not happen all the time...just occasionally, whether its summer or winter. Sometimes a month will go by and it won't do it, but then out of nowhere, it'll start stalling. I can not figure out what is causing it. I had a fuel pump replaced this time last year (about 155,000 miles), because it wouldn't start. I also had the injector assembly replaced at about 100,000 miles. The truck has about 175,000 miles, and other than this issue and some squeaks and the 4wd not working, it runs terrific. I've owned it since if had 58,000 miles. I will keep this truck until the doors fall off.

Someone mentioned it could be the Mass Air Flow sensor, but I don't want to drop $300-$400 bucks on that if it isn't the problem.

I'd really appreciate it if someone who might have had the same problem could chime in (or someone who knows what the problem is). It would help me out alot. I'd really like to see if I can get this problem nailed down. I am thinking about new shocks and tires but don't want to dump a lot of $$ into it if I can't keep it running properly. Help! Thanks!!!

 

Have you replaced your fuel filter? If you haven't, your going to be burning through that new fuel pump in no time!

-OSS

 

the fuel filter was replaced at the same time as the fuel pump last summer. I've put on about 15-20k miles on it since then. It started doing this about 5-10k miles ago.

Another source suggested the IAC motor needs to be cleaned/replaced. Same source mentioned cleaning the throttle body.

I'm gonna see what I can do myself before I try a mechanic.

 

Hmm....

yeah, I would try cleaning the IAC Valve, EGR Valve, Throttle Body, and TPS Sensor since they are all right there pretty much together and it's free if you have cleaner for them. I had a similar problem. Mine was a high rev at idle and then when I went to put it in drive, it would cut out on me. You might also want to check the adjustment for your idle.

 

anyone have anymore thoughts?

Anyone have a good step by step for getting to, removing, and cleaning the IAC valve and throttle body?

Tibby...mine is a 2002, and from what I understand, there is no EGR valve.

 

Well, it's all done.
Here's what I did:
-Took off the Mass Air Flow sensor, disassembled it, and cleaned it thoroughly with MAF sensor cleaner, then reassembled.
-Sprayed the throttle body with Throttle body/air intake cleaner, and brushed a majority of the carbon buildup off. repeated this step several times.
-figured out where the IAC valve was, removed it, sprayed it with cleaner, brushed it off, sprayed it again, repeated this step. When it was all clean and no more dirty cleaner dripped out, I re-installed it.

I reinstalled the intake and MAF sensor, reconnected the battery, and fired it up. After a couple seconds, it started up and ran fine. Drove to the gas station, poured in a bottle of Sea Foam, and filled the tank.

The stalling problem that resulted in two footed driving was an intermittent thing...it only happens occasionally...before yesterday, it hadn't happened for a month, and there have been no symptoms indicating a problem, so i won't really know if I fixed the problem unless it starts stalling again.

I'm not good at troubleshooting, nor am I much of a mechanic. I know how to research a problem, and I've been told that I have "mechanical instincts", but this all still took me about 2 hours from start to finish. We'll see how it goes.

 

Excuse the refiring up of a very old topic but, I did a search and this was the thread that seemed most similar to my problems. Almost to the T.

In the last few months my 1995 Vortec 4.3L would suddenly begin Idling terribly, ridiculous vibrations, stalling when decelerating coming to a red light, hunting/surging at idle. It would only do this off and on, maybe once a month. This week however, it started doing it constantly. To the point of where two foot driving has become the norm.

Yesterday I changed the spark plugs/wires/rotor/cap, replaced the TPS, put half a bottle of seafoam into the crankcase and gas tank, started up to the same exact condition. Went and had the trouble codes read.. 2 codes P0401 and P1406, so I cranked out $126 for a new EGR valve. Installed it, and she started up no problems. For all of 10 seconds. Same symptoms, no change.

Today, I removed the IAC valve and cleaned it with carb cleaner. Replaced it. No change at first, same symptoms but after driving for 5 or so minutes all problems went away. Smooth idle, doesn't stall or hunt anymore. SES light has remained off so far. I do not want to get too far ahead of myself and assume this problem is gone for good.

Has anyone dealt with an issue like this? I've been reading this forum for years now and love the advice I find. You all are awesome.

TC