hey blazer owners. i have a 97 blazer. 4.3 6 cyl. it has been good to me until recently. i have been having trouble it runs great when i first start it and go. but as soon as it warms up it starts losing power. i have changed everything i can think of on it. i got it to run better but still have a power loss. its not as bad. i changed the fuel pump,filter,regulator. changed cap rotor plugs. replaced all the sensors. done compress, fuel, and emiss. checks. now i'm going through tne wiring. does anyone know what could be wrong. i dont want to get rid of my blazer. please help

 

sounds like 02's are shot. they are the only sensor that takes over after the engine warms up might wanna check them out.

 

+1, also check out the cat, egr valve and maf sensor.

 

thanks i'll check those when i get a chance. i'll keep you posted

 

MAF might need a cleaning as well as the IAT (intake temp sensor - that lil plug in a grommet in the intake beyond the MAF) or the wiring is fubar on either.
Maybe the MAF wiring got too close to the exhaust?!
Check fuses as well for them.

 

thanks guys. i'll check all of it this weekend. i need my blazer back.

 

checked all o2 sensors. found 2 bad sensors #3 and #4. going 2 replace today. also found wiring to maf and iac bad. repaired that. seems 2 run better. as of now seems like it is running in limp in mode. hopefully o2 sensors take care of it.

 

I have the same kind of problem with my 93. But it also runs rich. I have no check engine lights. Would a 93 compare to a 97 in any way?

 

check your fuel pump. that is what mine ended up being. as for running rich. check all your vac. lines and maybe the throttle control. i didn't think the vac. lines would effect anything, but they do. good luck.

 

thanks for all the information. it ended up being the fuel pump. i will not by an after market pump again. bought the right pump for it that gm recommended. it runs great now. better than it has.