97 Blazer

Help with 97 LT Blazer. Had new Jasper engine put in about 47,000 miles ago. Gas mileage is not what is should be. Just rec. replace all O2 sen., plugs, and wires. Fuel filter has been on less than 10,000 miles. Been running great after plugs were changed, then yesterday it started cutting out. When you get to 1500-1800 rpm's it has nothing there. If you give it gas and go you see black smoke. Something is making run very rich. Anyone have any ideal's??

Alright, let's go down the list.

Have you ever changed:

air filter
Cap & Rotor
What plugs were used?

Also, I would take it back to who installed it because they could have installed the distributor a tooth off and the base timing is retarded.

Yes the air filter was changed with the plugs, which are AC Delco Plat. The only reason I had to change the wires were because I broke an end off of one trying to get it off. The rotor cap was not changed. But I will check about the distributor. I have taken to another mech. because it has never run like it should 100%. They had made the same kind of comment as though they thought is was out of time but it has no timming adjustment.Is there any way I can check the tooth setting myself??

Nope, take it back to the person who installed it.

You have a warranty.

Nope, take it back to the person who installed it.

You have a warranty.

BlazerLT is absolutely right, if you had a jasper engine installed I would bring it right back hand them the key and say fix it! Get whatever you can out of a warranty, I know I did.