I have a 96 Chevy Cheyenne 2500 with the 5.7 liter 350 engine. The trouble is that when I get up to between 55 and 65 I’m getting a jerky feeling-like it’s trying to skip or jump time, or like it might have some kind of fuel restriction. So far I have replaced the plugs, wires, and fuel filter, and even went as far as buying a new timing chain, Gear, and gasket set, thinking the chain might be a little slack at the higher RPMs. It has more than 158,000 miles on it. Someone said it might be a head gasket.
When it’s “skipping and jerking”, and I floor it and keep it floored for a period of time it runs very smooth. If I step on it from about 20 to 30 or so and accelerate through to the 55 - 65 range there are no problems. It only does what I described when I am under part-throttle cruising conditions. Just this morning I was driving along at about 30 mph and noticed a sputter sound as if it might be trying to back fire. Any Ideas on what the problem could be?
“Any Ideas on what the problem could be?”
Only about a hundred things. You say “still” having troubles as if you’ve posted before. If so, go back to your original thread and save everyone some aggravation by not going over the same stuff again.
Plugs? Wires? Filters? Fuel pressure?
Does this truck have a tachometer? If so, when it does this is the tach jumping up and down a few hundred rpm as it jerks? The question is whether or not you are have torque converter lock-up issues.
i have a Ford F-150 that was jerking. After our failed trouble shootings, a friend said to check the TP Sensor (tells how much the gas peddle is being pressed)and sure enough 2 of the three wires were burned off. Might be worth a check on your Chevy???
Have you cleaned the throttle body? Very cheap and easy to do. And, it could have a TPS that has some flat spots on it. It is easy to check with a multimeter, described in a lot of manuals like Chiltons or Haynes. The only cure for that is a replacement.
Thank You for your help. I did post this problem before, and I did go back to the original thread, but the replies stopped before I really got any answers so I posted again.
Thanks. I will check that out. Just this morning I noticed that as I accelerate up to 30 mph or so, the truck runs real rough and sounds like it’s trying to backfire. I keep hearing this pressure release sound. Like the sound you would get if it were trying to backfire through the carburetor. Could it be a sticky valve or something?
Thanks for the helpful tip. I will try to clean the throttle body and check out the Throttle position sensor also.
My Chevy does have a tachometer, but when I’m driving along at 55mpg and above, and it’s doing the “skipping and jerking”, the tach doesn’t jump up and down at all. I get a steady RPM reading. Just this morning I noticed that as I accelerate up to 30 mph or so, the truck runs real rough and sounds like it’s trying to backfire.
Checking the TPS is very easy if you have an electrical meter - just back probe the connector and with the ignition on (can leave the truck off) and the throttle closed you should probably have something in the are of about .5 volts. As you open the throttle the voltage should smoothly and gradually increase up to about 5 volts at WOT. (The numbers are just common - your exact specs could be different). It takes almost no time to do this depending on how hard it is to back probe or jumper the connector.