Ok here it is, I have a 98 jimmy 4x4 2dr with 134,000 miles.Alt is new, batt., k&n filter, fuel pump,water pump, pcv, ICM, spark plugs,wires, Dist. cap, rotor, fuel filter.So no codes thrown, one day after driving about 20 miles for about 30 minutes, I stopped at a store to eat lunch truck died after 15 minutes of idling. Would not start, for about 20 minutes. Finally started drove for about 2 minutes and died. Went back to pick it up after about three hours started drove it home 20 minutes away drove fine.Had the cat and exhaust replaced cause cat was goin bad, replaced with a bolt in magnaflow high flow cat and a 40 series flowmaster muffler dumped after muffler. Ran fine for 2 days. Drove again 20 minutes away at highway speeds died again. Replaced ICM started fine. drove home turned it off went to restart wouldnt. Finally got it to restart but after playing with the throttle pedal it hestates real bad. I'm at my wits end with this truck. I love the blazers I have three but I can't figure out whats wrong with this one. It seems to start after the truck has sat for an hour or two.
ANY HELP PLEASE, DON'T WANT TO GET RID OF IT. But I didn't pay much for it.


Ok now cleaned my MAF, and reset the ecm. Now doesn't seem like it will die but still stumbles real bad, in park and while trying to drive. Seems like no power.

As of today sat the 12th. I checked my plug wires to make sure they were connected still, took the egr valve, and blew out the build up, changed the egr valve with one off my other blazer. Drove it around thought it was ok drove it for 20 minutes beating it up. Ran great like new again. Thought everything was great and it was fixed, bout to shut it down and decided to wait till IAT got to 100 degrees or over. Since that's when it seems to mess up. It hit 102 degrees so I shut it down, restarted it worked fine but as soon as I stepped on the gas it would miss and act as if it were goin to die. Still stumbling and hesitating. And now won't start again. It seems to do this as soon as I hit over 100 degrees on IAT. HELP!!!

Ok just went back outside after letting it set for an hour. IAT is now reading 85 degrees when I started it. Started right up ran fine again, temp for IAT went down to 70 degrees runs great. So what could cause the truck to run like crap once it's at 100+ IAT ?????

 

Come on guys really need help here!

 

Security on at all? Sounds like an ignition switch...

 

I have never seen a security light since I bought this truck 2 years ago. And how would it be a ign. switch. If only does it after it gets nice and warmedup. Then you can start it again after it has cooled.My 2000 blazer has one and keyless entry. I don't believe this one does.

As of today I've swapped parts out of my 2000 blazer, the ECM is good, maf is good, map good, TPS is good, IAT is good, coil is good, collant sensor good, ICM is new and good.

I haven't changed the fuel filter after fuel pump change less then 1000 miles ago should of but didn't since I changed it when I bought the truck.

 

Think I got this thread confused with another one I was replying to... What can ya do...

And while I do appreciate the situation you are in, please try to be more patient.

When you replaced the ICM, did you get new thermal paste for between it and the heatsink/base that it mounts to?

What is the ambient temps when the IAT reaches 100+?

 

Ok just changed the fuel filter. Still dies when IAT reaches 100-+ degrees. Come people please HELP!!!!!!!!!!!

 

No didn't think to get the paste and I didn't get a new mount either.

I don't no what the ambient air outside is have no way of checking it, but ouside temp is like 40's and coolant is 150-175.

 

No need to post multiple times in a row... Edit! LOL

Anyway, if its 40 outside, the IAT should not read 100 unless the truck has sat and the intake has been heat soaked, but once running, it should read close to ambient. Sounds like you have a bad IAT sensor.

 

ok so went out to start truck started up fine. Checked the fuel service line, fuel sprayed out when truck was running. Truck died no fuel would spray when pressed in key was on. Is this how it's suppose to be?? Or somehow could my new pump be overheating or shorting out???

Swapped with one out of my blazer reads same thing. truck is just setting there idling, but even when I drive it around doesnt get any lower. just climbs.

 

Sounds like you have a wiring problem somewhere for the IAT sensor. What does the other truck show for IAT temps?