My 1990 4Runner runs, no powerat take off, then will run good, drive up any incline and has no acceleration, decelerates dramatically, loses power. No power in 4WD. Tuned up and changed oil, noticable improvement until we fixed AC, now back to original problem. Occasional, rare,sulphur smell. Friend said it is a burnt valve, the smell makes me think it is cat related. HELP!!!

 

i agree that it is CAT related...especially if you are losing power under load. a friend of mine had an older pontiac that was losing power, and it got worse and worse until it wouldnt climb his driveway, which wasnt very steep. do you have a rubber mallet? or a baseball bat with a towel wrapped around the end? if so...get under the truck and tap on the cat (when cool) hard enough to jar it a bit. if you hear any rattling, the CAt is bad.

 

Thanks for the advice, gonna try that ASAP! </P>

 

when the cat goes bad, what physically happens is that the inner honeycomb falls apart, and causes the exhaust pressure to backup into the engine...if you let it go too long, it can burn a valve.