Jump to content

99 sierra with no lowend torque


Recommended Posts

I have a 99 sierra with a 5.3 push button 4wheel drive, when i bought the truck it had tons of torque, it would spin the 35's that are on it if you fealt compelled to do so. now it has nothing, it will drive and actually feels to be normal if ur just running down to the store, but it won't do things like drive up on ramps or pull out a stuck vehicle, and the other day i actually got stuck on the boat ramp tryin to pull my boat out, it will tow the boat down the road and feels normal but on that boat ramp it just bogged right out wouldn't rev above around 1500rpms and would not move at all!!! also the "service 4wheel drive" light comes on after drivin acouple miles, I'm just lookin for any thoughts or ideas as to what it might be, thanks

Link to comment
Share on other sites

Oh yeah 10-4, and yeah i never even thought of the converters, good call, if i figure it out ill post what it was thanks.

I had the same problem on my Sierra. I ran trough all the checks on the MAF, TBI, vacuum leaks, etc. Here's a quick way to check the catalytic converter(s). Hold your hand up to the exhaust pipe while it is running and feel the pressure. If you've got dual exhaust with dual converters you'll feel the difference. Or if you have a friend with the same engine feel his exhaust and then yours. Yours will be much weaker.

 

It's was a PITA to pull my converter because I had to disconnect the pipes from the manifolds to get it off and, of course, broke off a stud, etc, etc, etc So you don't want to do it just to check the converter. In my case the canister inside the converter had come loose and was turned sideways blocking the exhaust. I used a long steel bar to knock the canister out, buttoned it back up, and it ran fine. Ordered the parts and replaced it later.

 

Also learned a cool trick for getting frozen studs out of a manifold - candle wax. Heat the stud and surrounding flange with a torch and press a candle against the joint. It will melt the candle and the wax wicks into the threads. The broken stud came right out with just a pair of pliers.

Link to comment
Share on other sites

  • 4 weeks later...

So ive cleaned TB, MAF, tested the TPS, everything checks out, had my mechanic plug it in and he came back with a bad ATC switch, i took the switch apart and sure enough some of the solder was cracked, I'm not totally convinced that's the isseu tho, the truck shifts pretty hard from drive to reverse, going into reverse the engine almost dies and then all of a sudden it catches and slams in, i kinda think its somethen electrical because iys been this way for awhile and I'm pretty sure somethen mechanical would've failed by now? I ideas from anyone would be awesome

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.