1988 4.9 6 cyl. 5-Speed tranny.From a standing start the truck hesitates and shutters slightly. 2nd thru 4th seems to be fine. Check engine lights at accelration. Mechanic tells me it's a clutch switch code. Would this cause my problem? Others say TPS is the problem. Thoughts please.....

 

I don't know how the manuals are wired up... on my auto, there is a RABS sensor on the rear diff (right on top) that gives info to the computer about speed and such. There is also a VSS on the side of the tranny where the speedo cable connects. I replaced both on my truck and that same hesitation went away. They are about $20 each and simple to replace.

I don't know if the manuals are set up the same way, but those fixed my auto. The TPS is a likely suspect too.

 

Thanks Alien, did you get a check engine light and did it direct you to the problem.

 

No code, but I don't think the clutch switch code is related to your issue. Seems to be something to do with the switch telling the computer that the clutch is in so that you can start the truck? I think there was a thread awhile back about the clutch switch, and a lot of good info - maybe some of those guys will chime in to help with that.

 

i have that code 67 and do not have any of your symptoms.

 

I don't remember exactly how the clutch switch works - seems like you really don't notice any symptoms unless you start the truck in gear (without the clutch in) - it'll let it turn over, surge forward, and scare the crap out of you.

 

Of course the clutch switch keeps the truck from starting until the clutch is pressed, but it also sends a signal to the computer so it knows the clutch is pressed. There's a reason for this, and until now I though it would only be for idle control. But now I'm thinking it also might work in conjunction with the speed sensor to help with takeoff. If the computer knows that the vehicle isn't moving and sees that the clutch is being released then it may adjust accordingly.