86 S10 vibration

[brooks4533@comcast.net]

I have a 1986 S10 w/ 2.8L fuel injection, the problem I have is I cant get it to run right, did a compression check and it was fine I have replaced the fuel injectors, fuel pressure regulator, plugs-gapped correctly, harmonic balancer, flexplate, fuel filter, TPS, It just wont run smooth. I checked the plug wires today, they are 7mm, so I checked on Advanceautoparts.com and saw that all of the wires available for my truck are at least 8mm or greater, would that make a difference. THe vibration is the worst between 30 and 40 mph. It is a really great truck in IMMACULATE shape, it doesnt leak or burn a drop of oil and I would like to keep it but it is just frustrating.

[Hammer Head]

Plug wires won't make a difference. Where's the shake comming from? I've had vehicles shake from a bad fuel pump, dirty fuel pump sock, broken trans & motor mounts. It could also be shaking because of out of round wheels.. I've noticed that out of round wheels shake around 45-55MPH. All depends on what & where the shake is felt.

[brooks4533@comcast.net]

I work at a wheel and tire shop, last night I rotated and balanced my wheels, the tires are only 6 months old. I really dont think it is the wheels. First I am going to check the fuel pressure, if it is low I'm probably going to install a new fuel pump, sending unit, and new tank-might as well while I have it down.

[brooks4533@comcast.net]

Today I installed a new oxygen sensor, egr valve and air check valve. Then I poured Seafoam down the throttle body. It really didnt help it at all. Now it sounds like it is missing.

[sammy]

I ran seafoam in the oil twice, changing the oil after both times, nothing. I ran it in the fuel at a level above the label's recommendation, nothing. Then I read on here to remove a vacuum line and let it suck the seafoam in. I used the brake booster line. It sucked it quick and then crushed the can with the vacuum! Smoke was enough so I couldn't see the neighbor's house. Then I took it for a drive, wow! This is after replacing sensors and sending units, even the ecu/ecm. Keep in mind, I have a 4.3 CPI so your results may vary.

[brooks4533@comcast.net]

So u ran this seafoam through the brake booster line before or after u replaced these sensors and what sensors were they?

[sammy]

So u ran this seafoam through the brake booster line before or after u replaced these sensors and what sensors were they?
throttle body, EGR, and something on the intake. The seafoam was after. I have to say, the backfiring has come back; pops once in awhile when I let off the pedal and has a little less umph when I get on it. No cat, dual exhaust to one flowmaster, then single 2.5 back, K&N filter. My issues started overnight too. I'll change my plugs soon if I can get to them. I'll have to remove the steering shaft to reach the ones on driver's side.