01 chevy express 4.3l 110,000.
My computer is reading severe misfire on cylinder 4 -the MIL light flashes
indicating severe misfire.
One problem, the van runs fine. Idles perfect never stalls, stumbles, smokes, skips, etc.
Plenty of power and good gas mileage.
I had a gas analysis done and its running super clean throughout the rpm range- super low HC's.
Several months ago the crank sensor went out so I had it replaced ( first time I ever let a shop work on my vehicle ). They over torqued the sensor to the point where it would not read correctly, it had to be shimmed to get it back into specs. Thats about when the severe misfire code showed up.
Even though the van runs clean I can't get my emissions sticker until
I get this one solved.
Anyone ever seen this before?
Guidance is much appreciated!
Brian in Atlanta
If that's when the code appeared then why not just clear the code, perhaps the problem no longer exists now that you've adjusted the sensor. Or, did you clear the code and it keeps coming back?
The code always reappears. disconnecting the battery on the
comp will do nothing. The code for the crank sensor was a separate code.
It has been cleared. It was only after the crank problem was rectified that
the p0304( & pending ) code was stored.
Man that sucks...I hate emissions Nazi's I am glad we don't have to go through that here, even though our vehicle laws restrict us quite a bit that is one thing we dont have to worry about.
You may have to do what's called a "crank relearn" so the engine computer will read the new crank sensor correctly. I ran into a similar problem on a late model Caddy. It would keep setting a misfire code even though it ran great. Doing a crank relearn procedure solved the problem. The least expensive way out will probably be to pay a good garage or a GM dealer to do it for you. I have a couple scan tools that will do the job, but the least expensive one cost me about $2500. I don't know if inexpensive scan tools can do the procedure or not.
I was just reading at the IATN website about crank relearn procedures done on a 4.3 in a 2001 Blazer and another one done on a 2001 Astro. I don't know if there's something different about the computer controls for a 4.3 in a 2001 Chevy Express.
I told the chevy dealer that they may have to run a crank relearn, but I don't
think the did the procedure. They looked at me like I had no idea what I was saying. Though I have no doubt i'm more skilled that most of their mechanics.
I guess i'll try and find a competent mechanic with the equiptment to "relearn"
the computer. I'll keep my fingers crossed and post back my findings.
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