My 1997 blazer runs great until it reaches operating temp. At that point the RPMs will raise to about 3000 at idle. After this goes on for about a minute then it starts to cut out with any gas. The RPM guage will jump all over the place, the engine chatters and no power. when it cools off it runs great again. I replaced the fuel pump, map sensor, crank positoin sensor, distributer cap and rotor. I had it scanned and the codes say #2 cylinder misfire and catolytic cover. Has anyone had this problem or know what it may be?

 

clogged cat? you could remove the o2 sensor by the cat to see if the truck runs a little better if it do your cat might be clogged .

also provide us with the codes

did you replace the cap and rotor with ac delco ? these trucks dont run right with any other markets

 

I did replace them with ac delco parts, but would a cat cause the tachometer to bounce around radically? I will get the code numbers as well.

 

id say trouble shoot it by taking the o2 sensor off on the y pipe in front of the cat

after that see if the truck runs a slight better

also the truck might sound a little terrible just letting you know before you get scared lol

 

Cool I will give it a try as soon as I get back. I am a pro trickshot artist (pool player)