weak engine 1996 s-10

Hello!

I've got a 1996 s10 blazer 4.3l with 120,000 miles. The engine in it was very weak for some reason. It would rev really high before it would shift. It actually spun a bearing after owning it for a few months and I had to have a rebuilt put in place. I had the engine scanned, distributor checked and everything adjusted to the proper specs. However, this engine is as weak as the first. It seems to have to work pretty hard to pull trailors or work the 4 wheel drive. Could it possibly be something in the transmission or the torque converter?

Thanks so much for your help!

Hello!

I've got a 1996 s10 blazer 4.3l with 120,000 miles. The engine in it was very weak for some reason. It would rev really high before it would shift. It actually spun a bearing after owning it for a few months and I had to have a rebuilt put in place. I had the engine scanned, distributor checked and everything adjusted to the proper specs. However, this engine is as weak as the first. It seems to have to work pretty hard to pull trailors or work the 4 wheel drive. Could it possibly be something in the transmission or the torque converter?

Thanks so much for your help!

The first thing that comes to mind is that you say you are on your second engine. I will assume here that the 120K is on the vehicle and not the new engine. If you are not receiving any codes but the engine is not peppy enough, your convertor might be restricted with crap from the first engine. There are procedures to check this. On the 96, it should have 4 O2 sensors. A real quick check, since I am sure you don't have the equipment, is to remove the pre-cat O2 sensor and drive it. If it is a little more peppy, suspect a plugged or partially plugged cat.

Have you ever done a tuneup?

Changed the fuel filter, cap and rotor, plugs, air filter, pcv valve?

It would seem to me that if you have a good running engine, ie no nocks, rough idle, smoke etc than the problem must be in the drive line.

First I would check plugs, air filter, fuel filter, distributor. Any one of these would cause a weak feeling motor. If all that is good consider changing the tranny filter, rear diff fluid.