First time posting! I have a '98 Blazer 4X4, 4.3L. This past summer in hot weather (100+), whenever I would let it idle in one spot for more than 3 minutes, it would hesitate, stall, and not restart (just turn over). It seemed to be heat induced, for when it cooled off for a few minutes, it would restart. As winter weather cooled, it had not been a problem. However, yesterday when I took it to get a smog check, after the warm up cycle, it did it again. After a brief check confirming 60 psi fuel, proper spark at the plugs, and about 5 minutes of cooling, it restarted. The smog guy was baffled. It has been getting progressively worse mileage, and seems to lack some power, especially at higher rpm and hard acceleration. Reading the posts, I'm now wondering if it could be a fuel pressure regulator, but I don't smell any excess fuel. Any ideas, or how I can test it?

 

get your ICM (ignition control modual) tested at your favorite autoparts store first.

They are mounted to a heat sink, if the get too hot it screws with your ignition spark timing. Failure to start when hot is one indicator.

Welcome to the site.

 

Thanks, I will look for it. Will it test as defective since it runs good when normal or cool operating temperatures?

I also forgot to mention on my first post that there are no error codes, and I put on a new catalytic converter (thinking it may have been clogged), recent fuel pump, and new fuel filter. I have not changed spark plugs.

Thanks

 

It will only test defective if you test it like 10 times in a row. you want it to get hot and most autoparts stores know this. If not, ask them to test it a bunch of times, 10 is an exageration, like 5 times or so will do it. Careful, it will be hot to the touch when tehy are done testing it.[:@]

 

Well, the auto parts store didn't have the adapter to test it, so I bought one anyway. Seemed to run good for a while, until I was able to get it warm enough. It did it again, and this time threw a code P1351 with a check engine light. Now it is stalling more frequently (after about 15 minutes of solid driving). Today, when it did it, I immediatelyhooked up the old ICM, and it still wouldn't start for a few minutes until it cooled down a little. However, once it does restart, it is more sluggish and lacking power. I'm debating on changing the ignition coil.
I've read many posts with people changing everything imaginable, and still having problems. My fear is that if I take it to a dealership, they will rape and pillage my wallet and still not fix the problem. Any suggestions???