LLY power loss

[RADAR]

Empty this "lly" truck runs fine, but mileage is still bad. 12 on the highway or in town, used to get 16+ in town and 19 on highway. My truck is having problems pulling 5,000 lb trailers and seems VERY sluggish. Mileage is down towing from 14 to 9mpg, so far clutch fan has been determined to be bad (temps had gone up some while towing) fuel filter seems to be fine and computer has issued no codes.

Any other ideas what the problem could be? thanks

[Black95TD]

I guess this is where a boost guage would be good. My old 95 was down on power and smoked quite a lot. Finally found a bad wastegate solenoid and improvement was dramatic. I currently have a PO299 code and low tubo boost. I would hate to tow anything until its fixed (Mon. I hope). My light throttle driveability and mileage is still good though. Sure sounds like low boost could be an issue. How has the dealer been in responding? Maybe a different dealer is in order. Good luck!

[Kennedy]

I guess the cat could be plugging. Have you had all ECM programming updates done?

Another possible solution: http://72.22.76.69/tdpforum/showthread.php?t=23222

[RADAR]

Black95TD

Gauages would be nice, but no, I don't have a boost guage. Truck is not blowing any smoke. So far dealer is still checking truck and I should hear something sometime today. Thanks for the reply.

[RADAR]

Kennedy,

""I guess the cat could be plugging. Have you had all ECM programming updates done?"" -- No, I have not had any ECM programming done, What updates are you refering to? I assume this is something the dealer does? Thanks

[Kennedy]

There are updates for surging, intake popping sounds, etc. I'd have them all done...

[RADAR]

thanks Kennedy,

They "GM" claim all my updates were already up to date. Dealer replaced the Clutch-fan. Mileage coming home (25 miles) on highway was about 18mpg. Do you think they did updates and didn't tell me or would the fan cause this much drag on the engine?
As far as power loss towing, I won't know the answer until I try to drag it up a hill. I'm still puzzled as to if all this could be the result of a bad clutch fan.

[Mark Rinker]

My '05 LLY is similar. Runs fine, pulls fine, but mileage sucks compared to the LB7s. Granted, its bone stock, but what bothers me is that the mileage was good for the first 30-40K, then dropped off and won't seem to return.

9mpg for the last 6,000 loaded miles. Thats a 26 gallon tank of fuel every 200 miles, folks...the good news is that it saves my lower back (get out and stretch) and I've caught two tires on their way down with road debris by stopping frequently and checking the trailer.