spark plug suggestions

[MAKG]

No, you have an uncontrolled variable and you don't know how the spark plugs affect that variable. It's not possible to separate it from a real effect.

Maybe your problem is that your coil pack is internally shorted, for instance.

 

[Nailzs]

how do i find the problem then? no cel, runs good, good vacuum
bout all i got is a slightly rough idle.
its hard to diagnose something when all you have is a slightly rough idle and you have no idea what is wrong...

 

[MAKG]

How can the vacuum be steady if the idle isn't?

I'd try a cylinder balance test to see if any cylinder is dead.

 

[Ozwynn]

why you guys trying to argue this stuff with Mr. Gross? you guys should know better. He is a pretty smart guy when it comes to this stuff. put some 4.56's in it, solve your other variables and do your test again...............

 

[bro2]

I was told in a engine diagnostic class to run the oem plug for best results.
bosh platinum spark plugs are the only spark plug that I have cause a running problem.

 

[woodyedmiston]

Spark Plug Suggestions

Eleven miles per gallon. I was getting 19 when I did some work on the motor and discovered that the spark plugs that I was supposed to have installed two years ago - were never installed. That means the truck had over 220K on the plugs that came in it from the factory. They didn't look pretty either. But even with a gap that could be measured with plywood it was getting better than 11mpg. I've really noticed a difference since I put in new plugs.