RPM Limit ?

Tahoe can be running absolutely fine, then suddenly jerks like a bad misfire, lose power like it won't take fuel and limit engine rpm to 2000 rpm. I pull over, put in park try to rev up engine, will not go above 2000 rpm. Turn off and let set for a couple of minutes. Starts just fine rev engine greater than 2000 rpm and it seems okay. May repeat after get going, but may not. Seems to occur under heavier load when need engine rpm to increase above 2000 rpm, like going uphill or pulling out into traffic. Seems like possibly a sensor that is rpm relevant? Thanks for any help.
1999 Chev Tahoe LT 5.7L 4wd 4 door

ICM failing.... pull and have parts store test it several times to get it pretty warm....

Would test the fuel pressure also.

lesterl said:

ICM failing.... pull and have parts store test it several times to get it pretty warm....

Click to expand...

Please excuse my ignorance, but since the Tahoe has never, ever failed to start and awalys runs smooth at idle, how is the Ignition Control Module involved ?

AFAIK the ICM actually controls the base timing and the PCM sends a signal to it to adjust the timing forwards or backwards from base.... Now that being said, it isnt hard to test with a machine at the parts store and it would be a good place to begin since you dont appear to have started looking at anything. I would also check the CKP sensor in the timing chain cover..... IDR if it is the 5.7l or the 4.3l that had issues with an aftermarket cover being slightly off and or a bad sensor.