5.3 runs very rough under load

[SLCHOE]

Good move. The downstream O2 should read a steady ~700mV if it's doing it's job. If it's near zero mv and flatlined (using a graph) it's dead. The exhaust side of the cat, when up to operating temp, should be hotter than the inlet side at 1500 rpm.

 

[VikingTrad3r]

i am lucky, this turned out to be a false alarm. the wind really cools off the driver side exhaust right behind the cat. i had the truck on ramps, into the wind.

i took it for a rip and checked with a temp gun and its all goid b

 

[SLCHOE]

Sweet!

 

[George Tahoe Man]

2002 Tahoe 210,000 miles. Engine starts right up and idles smooth in park. In park engine revs freely with no hesitation or noise. In drive the engine is smooth if you keep the throttle low enough to keep RPMs under about 1800-2000. Give it any more throttle and the engine vibrates, has no power, and pings badly. To get to 60 mph on flat ground takes about half a mile or longer of light throttle. Drives along fairly smoothly in overdrive at around 55-60 mpg and 1800 rpm.

The only engine code is for a MAF sensor which I have replaced, and the usual gas cap code.

Any ideas?

Having exact problem, Help if any one can.

 

[M1Gunner]

a Very simple way to check if your cats are clogged is with a vacuum gauge connected to your intake manifold. Doesn’t even involve you driving the vehicle.