Have you ever passed anyone on a 2 lane road? Watch your tach and see what it does when you floor it and it down-shifts.

 

I haven't in my Blazer, yet but I'll try one day when there is someone that goes slower than 65 on a 2 lane around here.

 

You will certianly exceed 2500 RPM.

 

Thanks, I see what you mean, but I didn't actually pass someone, I floored it just for the sake of it; and my Blazer almost went dead on me, I guess its one of those things that has to do with the throttle body bein worn out. It's not my alternator, it read 14+ the whole time.

 

Changed alt and no differance....i took it out on the hwy and with everything off it hit 14.3 volts....clicked a/c on and it droped 13.1 volt...hummmm ecm problem???

 

Do you know your engine's horsepower? The A/C uses the main belt when switched on (that's why people turn their A/C off to save gas). Come to think about it, you need to check your relays and computer and make sure everything is working properly; cause when you switch your A/C on, the computer is supposed to increase the fuel input to support the A/C + the forward acceleration. (BTW, what's ecm?)

 

Its a 1999 4.3 it runs great, will smoke em up....It gets 14mpg with A/C on and 18MPG without. When I first got it had an issue with rotten battery cables but replaced everything. And ecm PCM whatever...powertrain controller.

 

Could very well be the ecm.