Need some help, Just installed some mach2's. With the drag box on 1,3 the truck shutters at about 2300 to 2500rpms then smooths out a little but continues. I change back to the reagular comp, it still did it but not as bad. with the box off it was barely noticable but still there. Boost pressures w/ drag it will start around 32psi, comp its around 28-30, with no box around 28. Its a random shutter no real rythm to it, but you can hear a difference in the exhaust note when it happens. Could this be valve float?, due to rpm and boost pressure. Thanks for any ideals

 

anybody, hmmm?

 

I've had a problem that sounds similar to yours but at much lower rpm. It turned out to be the transmission mount that got delaminated and the engine was acually tilting forwards and back a little while under high torque.

HTH

AlpineRAM

 

I was getting a shutter in 6th at lower rpm's while towing. I just figured it was the injectors. I kinda drive around it by reving higher in 5th or just staying in 5th till I get more speed up for 6th. No issues empty.
CJ

 

thanks for the responces, Alpine I will check the motor and trans mounts. Just driving around now without the box on.

 

Yeah, I had the same problem with a broken transmission mount. I replaced it, but now I have a squeak that I think it related to the trans mount, but I can't pinpoint it.

 

You can try to losen the bolts of the trans mount and retightening them again- sometimes it gets a little pressed in and there is some tension on the mount that pushes the engine forwards or backwards- then the engine mounts can squeeeeeek a bit.

AlpineRAM

PS-I didn't see the tranny mount being bad until I lifted the tranny with a bear claw. Visually it checked out OK first.

 

all the mounts looked ok, but I didn't take anything loose. This evening I wasn't watching the boost gauge and hit 30psi. The stumble was there, then it idlied ruff. I tapped the pedal and it went back to normal. I'm thinking it something engine related. I will recheck the mounts again. thanks

 

I will have to try that. I never thought about the trans mount pushing foreward or backward on the engine mounts, but that would definately make sense. I will try loosening them up, and straightening everything out.