Mack 1999 RB E7 350 18 Speed Mack
I have had low power issues since I purchased this truck over a year ago. I have checked the pressured side of the intake no leaks, replaced the turbo but only have 12-14 pounds of boost. Lately the throttle pedal has begun to act erratic as in no throttle response at all but if you wait a few moments or even minutes the pedal comes back to life and I noticed yesterday the speedometer falls to zero when the pedal drops out. I replaced the pedal assy. when I put the truck on the road a year ago. The limp or low power mode from the throttle pedal means you have to to double tap the throttle to get more response even between shifts. I have had the truck to a couple of shops and they say take it to Mack and have the ecm flashed to start.
Thanks for your advice.
Keith