I have a 95 blazer with the vortec in it. The motor and tranny supposedly have 40k miles on it. When I go to stomp on it it downshifts but just revs up and doesnt go anywhere. Normal driving is perfect, shifts when its supposed to and doesnt slip or anything like that. Thats why I dont believe its a tranny problem like all the other forums say it is. I also have a 99 grand prix doing the same thing. Tranny fluid is at a perfect level too. Someone told me it might be a fuel problem. Im sure this question has been brought up quite a bit since 2 of my cars have the same problem. Can anyone help me out??

 

I know a little more about the grand prix then the blazer, but I know the grand prix will have computer controlled torque management. I suspect the blazer does too, but it is older. Anyways, if the pcm tells the transmission not to engage power on downshifts, it won't and that is programmable. It also means the transmission is fine and may operate fine in all other situations. Why the programming would be out doesn't make any sense either though. Has any external tuner been used before?

 

Not that I know of, but I just got it a week ago. Trying to figure out a different problem with it running sluggish which is another problem. Thats why I was thinking it was a fuel problem. Just had the caty. converter removed but that didnt fix anything. Not sure what your meaning by external tuner? Is that like a power chip thing?

 

If the RPM goes way up and it does not move faster then that is a typical trans problem. If you floor it and the RPM does not change much at all if any and it does not go faster then you most likey have a engine type performance problem.

 

I doubt it would be a tranny problem, both of my gm vehicles are doing the same thing. Both shift perfect from first gear on. Im leaning towards a fuel problem since after I changed the fuel filter on my grand prix it help out alot and gave me a little more boost on the passing gear.