Truck won't hold a constant speed

Asked by Apr 23, 2017 at 09:58 PM about the 1993 GMC Sierra C/K 1500

Question type: Maintenance & Repair

While I am driving down the road above 40 mph I
always have to accelerate because it won't keep a
constant speed and when I do accelerate
sometimes it will sit there at the same rpm and all
of a sudden jump up to high rpms and other times
it seems as though it doesnt want to accelerate to
me it seems as it would be either the trans is going
bad or the tps is going bad I checked the trans fluid
and its a good color and it doesnt smell burnt

4 Answers


93 is OBD 1 you may need to find a shop that still has some of the old test equipment for data scanning, it is possible you have a dead spot in the TPS range sweep or maybe even a fuel pressure or flow problem.

I don't have any dash lights on I do have cruise control but it doesnt work anymore I had the trans rebuilt also about 3 years ago it now has about maybe 25000 miles on it give or take some but when it was rebuilt it also got a rebuilt torque converter

My reason for thinking it was the tps was because I would push down on the pedal and it wouldnt do anything so I would keep pressing down until it did and thats when it would jump up into high rpms

So if the motor were to be bad or not in good shape it could cause that lagging feeling to feel even worse than what it should be my #8 cylinder has leaking valve guides thats why im asking

Your Answer:

Sierra C/K 1500

Looking for a Used Sierra C/K 1500 in your area?

CarGurus has thousands of nationwide listings and the tools to find you a great deal.

Postal Code:


GMC Sierra C/K 1500 Experts

  • #1
    Andrew Olsen
  • #2
  • #2
    John Saffrahn
View All

Related Models For Sale

Used GMC Sierra 1500
186 Great Deals out of 11,190 listings starting at $3,880
Used Ford F-150
510 Great Deals out of 11,200 listings starting at $369
Used Dodge Ram 1500
47 Great Deals out of 496 listings starting at $3,800
Used GMC Yukon
9 Great Deals out of 1,110 listings starting at $4,995
Used Chevrolet Camaro
1,085 listings starting at $4,500

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.