92 yukon has no powah...ideas?
 

this is our towing vehicle, never really had problems besides th etrans which was just rebuilt maybe 5k miles ago. we go to drive it and it cant get out of its own way. not even towing anything you cant get up a hill. it has a bad exhaust leak thru the muffler but that wouldnt make it have no power would it?

clogged cat?

350 TBI?

SES light? Timing? Bad gas? Cloggeg cat like he said?

350 tbi is correct.

Symptoms?
Does it back fire?
Does it sputter?
Does the engine remain smooth or does it buck?
Does it have a stable idle?
What does the exhaust smell like?
Is the oil clean?

Need more info than it just doesn't have power. There are so many ways an engine can be down on power that all anyone could do is guess unless more detail is given.

still seems smooth. when going up a hill it will downshift to 3rd and sometimes to second and it slams into second hard. no back firing.and i havent smelled tghe exhaust.

When was the last tune up? Fuel filter, PCV, timing checked?

What grade gas are you running? I had a 93 PU and when prices hit $2.50 a gallon a switched from premiun to reg, and found out quickly the #&)%*?^ thing would only ran on Premium no matter where I put the timing. When runnning reg it would start to ping and overheat when going up grades, no way I could tow with it if running reg!

we always ran regular, always ran fine till the most previous time we started it.

i thought tune up also but it doesnt seem like a tuneup

Did you even check to see if the cat was clogged?

What is the fuel pressure on the return side of the TBI?

Answer these questions before you keep guessing.

i havent had time to work on it. once we have a minute we are going to drill holes in the cat to see if that what it is. im thinkin it may be that cuz we park it in the back of the yard and we think mice may have tunneled into the exhaust and made a nest there....

Does the exhaust make a hissing noise when you stand on the gas? That is a sign of a clogged exhaust. If the cat is done the exhaust will smell like rotten eggs.

So you are going to destroy the cat to see if it is ok? Isnt that like cutting off your toe to see if it is infected?

its rusted as it is so itll need a new one and i get free/discount parts.

then why bother with drilling anything? just replace it if you suspect it.

we dont have alot of money atm so we are just going to try it and see if thats it before we go replacing stuff.

eh?

My thoughts exactly Mike. Either the cat is free or it isnt.. Plus once the hole is drilled the cat will need to be replaced anyways.