Revs great sitting still but....

[ArkanSHO]

Pulling up to some guy in a parking lot here with Iowa plates waving his arms franticly, I now have a new friend who just bought an 89. He had just replaced the radio in the parking lot and couldn't get it to start. I pointed him to the checking for spark then fuel. When no spark appeared he eventually got to the ignition module and replaced it, but called a few minutes ago in a very panic state with this new problem. The SHO will rev great sitting still but runs like a "Winnebago towing a trailer" when it is in gear (his words). . Not being an experienced with GEN 1's thought I would ask for some expert advice if this is one of the obvious problems that I would tie bad plugs, wires, fuel pressure to or if I should tell him to look elsewhere?
Thanks
Carter

 

[96lt1]

i just went thru the same problem with my 89. mine wouldnt rev until it hit about 2k rpm's unless u gave it just the littlest amount of throttle. for me it was my throttle position sensor. i took it to Autozone, had it tested and it was bad. put the new one in in their parking lot and it ran good as new. hope this helps.

 

[projectSHO89]

Ask him if he has a Winnebago tied to the rear bumper.

Seriously, tell him to go for a short drive, then see if any of the wheels is particularly hot. Don't touch them, just hold a hand next to the wheel. A dragging brake can cause this problem.

Also, have him get the car up to speed, then push in the clutch. See if the car revs normally then. If it does, there's some kind of problem only when the car is under load.

See if the radio is tuned to the wrong station. Have him unplug it to be sure.

Steve

 

[BeatDaSHO]

maybe his secondaries are stuck open. This will decrease low end power. tell him to check that they open at 3850 rpm.

Greg

 

[ArkanSHO]

Thanks for all the suggestions, turned out that it was fouled plugs. Thanks again.