i have a 1991 bonneville le. when i set the cruise control, the car starts to accelerate very rapidly and will not stop accelerating until it has reach top speed. a mechanic suggested replacing the cruise control module. however, i have been unable to find the part locally. any suggestions.

one other problem is that it will occasionally misfire.

Usually the complaint is the reverse, it does not accellerate very rapidly on resume. Our 90 Bonne will kick down almost immediately so is a Pontiac trait.

You might try just losening the cruise cable (move the clip to a hole further out on the servo arm) so that a given cruise diaphram position will not move the throttle plate as much.

BTW the last time I looked the cruise control module was nearly U$200 and the same module was used on many many GM cars of the period.

Misfire is something else and most likely related to weak secondary ignition - coilpack, wires, plugs (75% likelihood); dirty injectors (20%); or other (5%)

yeah sometimes when i have my cruise set it starts to slow down then i tap the gas and it sprints up back to speed. :?

[quote="ollieg"]i have a 1991 bonneville le. when i set the cruise control, the car starts to accelerate very rapidly and will not stop accelerating until it has reach top speed. a mechanic suggested replacing the cruise control module. however, i have been unable to find the part locally. any suggestions.

one other problem is that it will occasionally misfire.[/quote

padgett is right, most times (as in my case) it'* the opposite....
Someone mentioned to me about "rebuilding the servo" but I don't know what that means.

Under the hood, in between the throttle and the master cylinder. Threre is a vacum line that plugs into this device with a throttle cable, well take that out, and test it. make sure it works, hold the vacum input and try to pull out the output shaft make sure it doesn't move or is hard to move. Basically make sure it blows and sucks air when moving the output shaft. put some light oil [3n1 would work fine] down in the vacum input, and through the open area near the output shaft. Test to make sure it doesn't stick, and all is well. as long as all these things check out, that is not going to be your problem.


-justin

PS: I hope this is accurate enough, i've never done this on a Bonneville, but on my dad'* suburban'* wastegate controller was a similar operation. If you need me to take a picture of where this thing is, [my description wasn't quite all that great] i'd be happy to.