ok I got a 2001 blazer , when first started it runs fine but when it get about 150 degrees it starts running like shi* it's got no power ,and it surges you can watch the rpm gauge flutter about 500 to 1000 rpm up and down while driveing under load if you baby it its not as bad some time you can feel it clear up then goes right back to running bad I've changed plugs,wires,cap,rotor,air mass flow sensor,cam sensor and it all didn't help . when I changed the cap and rotor it ran perfect for about two days then right back to it's problem I don't know what eles to try PLEASE HELP !!!!!

 

Is the Service Engine light on?

 

it comes on once in a blue moon if you on the peddle hard it comes on but it brings up the code for the mass air flow sensor and I've already changed that

 

I think I got bad plugs ..I'm running the bosch plattinum's and just read the spark plug thread and read that the bosch plugs are junk and don't work in the 4.3L so I'm goin to try changeing plugs and new MSD coil pack and see if it works but still open to any info please!!!!

 

iv been running bosch plugs since this truck was new i was surprised when i read that thread that they wernt good in these trucks i might try different ones to see if i notice any difference i have 210,000 on the truck and about 200,000 have been with bosch platinum 4 plugs

 

yeah I got 164,000 on mine but I got it used and wrecked I've put 3,000 on it but I've used bosch in everything I've owned except my 2004 GTO I had but we'll see if it helps I'm goin to AC DELCO rapid fire plugs

 

Sounds like the same problem as me...see my post today it says -new to forum-.