Spark Plugs, Engine Shake??
 

I took all the plugs out and well need some assistance- plugs 1-4 were fine and had normal wear, plugs 5-8 a different story plug #5 had carbon fouled, plug# 6 normal wear, plug#7 Bad oil fouled, plug#8 bad oil fouled both 7-8 were pretty bad and i replaced all but what is the problem on my 5-8 side of the block?.

Then as i started it up after plug change the engine was shaking pretty bad i then turned up idle a bit and it stopped shaking so bad like before but the idle was so high it wants to keep running after shutoff. I then backed off idle enough to stop that but it still shakes some is that ok whats up with the shakes :confused: ?.

Re: Spark Plugs, Engine Shake??
 

Crossed wire?

Plug gap.

Grease on plug wires? Or lack of, cousing spark jump. *electronic ig.

Re: Spark Plugs, Engine Shake??
 

Yeah... if it ran alright before, but runs poorly now, I'd say it is either a crossed wire or a bad set of wires that are now touching each other.

As far as the oil/carbon... some of that could be as simple as a bad plug or wire or bad gap on #5....

7 and 8, well, oil in the combustion chamber is never a great sign. The hope would be that it is minor and a better quality plug might do the trick in burning that off rather than letting it accumulate...

One of the things that I like to use for cleaning that stuff up, it especially works well on fuel injection engines, is Valvoline SynPower Complete Fuel System Cleaner... I've seen the stuff work wonders when I was running out of ideas, and if your engine has already seen its best days, it might be something to check out.