After fire

[Chevk587]

Hey guys got a serious problem , so my 87 blazer 5.7L run great when cold once it get hot / ran for awhile and not engine temp wise just running for awhile starts to back fire misfire and die if I keep on the throttle . If I stay at like 1000-1500 rpm it's ok but push it any further then as stated above happens . Any ideas cold runs great no problem . I'm thinking clogged cat or a coil going bad any suggestions???

 

[Stomis]

Coil or ignition module would be my first place to look.

 

[Fordum]

Coil and module are the easiest things to check. There is a trick to check the cat that I don't seem to hear about as much as I used to.

You pull the oxygen sensor and attach a pressure gauge to the port. A stopped up cat will show up as excess pressure.

 

[Chevk587]

Ahh good trick didn't think of that ! Gonna change the coil first cheapest and easiest !

 

[ktmoutfront]

I had that issue on a truck and it ended up being a TPS.

 

[dyeager535]

I don't think I'd just be randomly changing parts, but that's me.

Plenty of HEI testing procedures to be found on the web, all you need is a multimeter.

 

[Chevk587]

I'm pretty familiar with testing procedures it's an intermittent problem thanks for your 2 cents ! Just looking for a place to start hard to fix something that's not always broken !

 

[rampage]

Have you pulled the plugs and check their condition to see how each cylinder is behaving?

 

[Chevk587]

No I haven't I will at pismo beach this weekend without my blaze gonn fix it ASAP. ! Pismo is sick!