Troubles with horsepower

[Lance]

I recently purchased a 1995 GMC Yukon and until a recently had been working well. At this point, the Yukon has major troubles traveling up hill. It won't appear to get any driving power despite having pushed down on the gas pedal to get it to kick into overdrive. It just doesn't seem to be getting any power to have any getup and go. On flat surfaces, I have to kick into overdrive just to get up to 30mph to get out of intersections.

So far, I have replaced a fuel filter, an EGR valve, air filter, coil spring, cleaned out the carburetor as well as making sure the cap and rotor was free of corrosion and buildup and that it wasn't cracked. Still to no avail. I am positive it isn't the fuel pump because that either works or it doesn't. It also seems to choke out in the carburetor like backfiring. Today, I plan to check the plugs and the wiring as after replacing the coil spring, the check engine light now comes on after previously having it checked with no error codes.

If anyone has any advice, feel free to let me know. I would appreciate your valued input. Thanks in advance.

[John]

First of all, you should have a 5.7L throttle body fuel injected engine, not carbureted. Beyond that, sounds to me like you definitely have a plugged catalytic converter. Sounds like if it is making a noise that sounds like backfiring, you are probable building up excessive exhaust gases, due to the exhaust being restricted, that can not make it out the tail pipe. That is the easy part. The tricky part now is figuring out why the converter failed. It is the ONLY part on a vehicle that should never wear out, but unfortunately, due to general lack of properly maintaining a clean fuel system, and induction system, the air/fuel ratio gets thrown out of whack very slowly over time, leading to excessive wear of the catalyst. My advice would be to replace the converter, then have a thorough cleaning of the air induction and fuel injection systems. The product that works best for that is BG products. You can obtain it at about any dealership. Or visit bgprod.com . Good Luck!!