Had a very similar problem with my 98. Try driving with maf sensor unplugged. If it runs like normal thats your problem.

Fixed it!!! :icon_eddie:


No More Huge Fan noise under hood and no more power loss when engine is warmed up!!!


I after spending thousands of dollars on various sensors and repairs, fuel injectors, fuel pumps, etc. I went with this AC Delco Fan Clutch ACD# 15-4684, GM# 15154901


This part cost me about $90 and shipping.


The fan clutch was one of the items I replaced from the get-go, but used a different part/manufacturer and it cost about $40-$60 at the time. And my issue was still present :icon_screwy:


Once I installed the new Fan Clutch from AC Delco, the huge fan noise was present for about 5 sec, then dissipated. I ended up driving from Arizona to Denver the very next day (about 900 miles). Not ONCE did the fan/power loss issue surface......


My Truck stayed under 190 Degree entire way through! :icon_beerchug:

Congrads! I can see how the new fan reduced the roaring noise, but how did the fan help the low power/no acceleratin part of it?

I believe the first time I replaced the fan clutch, it was either a bad one, or just functioned/engaged once the engine temp hit around 130-140 degrees. After knocking around the idea that the problem only occurred once the Fan clutch would engage at such an early temperature, I tried to think "How do we keep the Fan Clutch area COOLER?" The only conclusion I had left was to try a different fan clutch...
:icon_that:

I know many are finding out that buying OEM aka AC Delco or Delphi up front is cheaper in the long run. It is hard to do when you are on a tight budget and you are presented with 'bargains' on the net /ebay. But I like doing the job once and not chasing around after an illusive trouble. Exp. when you thought you had fixed a problem with inexensive parts. Thanks for posting your search for the solution.