Multiple codes P0141 P1351 P0161 P0306

[cwillbur]

1998 GMC Suburban K1500 5.7 Multiple codes P0141 P1351 P0161 P0306

 

Many hits online about intermittent misfire. Many "solutions",,,

 

>change to updated fuel injectors - worked for some

>replace valve springs due to factory weak springs

>change distributor as gear may be worn

 

All have changed plugs, fuel pump, wires, cap and rotor etc.... with no results.

 

My engine is running fairly well. Has slight vibration at speed. I would say about 97% okay.

 

Trying no narrow down the 3% that is wrong without changing everything under the sun that others have tried and did not work.

 

In addition to the very slight dynamic engine vibration, the tailpipe is black with soot, but I'm getting close to 16mpg so not losing much if any mileage, and not losing any power. (I drive about 65 in a 70 zone and drive easy, so got closer to 18mpg with my identical 98 GMC Suburban, so 15.75mpg is a little off)

 

Any brilliant ideas that may have something to do with all 4 codes being connected do to some fault?

 

Needed tires so got some today, and vibration went down a little, but still present (my passenger seat makes noise with the vibration). Less noise, but still present. Assuming old tires were a little out of balance, but new tires didn't fix the vibration. Assuming the engine is creating the vibration. Engine has 192K miles and truck is new to me. Runs and drives excellent. Check engine light is on and would like it to go off. I am not one to drive a vehicle with the SES or CEL whatever on. I fix things.

 

Edited: Had my middle seat folded down and pressing on the back of my front passenger seat. Moved front seat forward, and vibration "noise/noisy seat" disappeared. Apparently it didn't like to be wedged against.

 

Thx. Carl