shaking when holding speed

[robztheman1]

my 92 s10 shakes or jerks when i try to hold a constant speed .when i accelerate it doesnt do it and at abou 50mph i cant realy notice it. i tried to change plugs and wires,it dident help. 2.8 LTR moter 2wheel dr. 150,000 miles. ps. not trans problem.........................any 1 help please

[herkyhawki]

If the vibration is speed related and not RPM related, you will not fix it by working on the engine.
Check tires, front-end alignment and driveshaft U-joints. A bad u-joint will sometimes only shake at certain speeds and be smooth above and below that speed.

[robztheman1]

sorry thanks for response but the motor is dieing out on me and its running very rough.not u joints or drive train. i should of put that before.sorry was very sleepy.anyway not sure if egr or something electronic. i also put new fuel filter cap roter it was backfireing out carb but with prem. octane it does not do all this if i the check engine light comes on after i drive for 1 or 2 hrs.
please help ................thanks rob

[DavidPT40]

My 1996 S-10 is doing the same thing.

A friend of mine said that it could possibly be the coil, you may want to check into that.

[robztheman1]

hey thanks i will try that. could be that i guess not getting hot spark.

[rhandwor]

I worked on my son's 92 chev.pickup which had a 6cyl I went through the electrical system and got most of the shaking out but going up hill it would just start shaking. Somebody had installed an aftermarket egr valve. It had a slot for a washer with a certain size hole. I talked to the previous owner who used to work for me but was a junkyard mechanic at this time. He didn't have any spacer I looked for some I had saved but they wouldn't fit. I found a washer the right size and thickness and tried about 3 or 4 hole sizes until it ran correctly.

[robztheman1]

it was the EGR solenoid thanks lot 4 the help[