Ok heres some weird s(*& I did a tune up basic new wires, Distributor cover and cap and took a chance on some bosh plugs the +2 not the four( I hear the four are for rice burners anyway), My ride rode well so I couldn't complain however I must admit to every four tanks running some fuel injector cleaner and a good little road trip to clean out my lines. Not too long after I added a flow-master 40 series and as always loved the little extra power and gas mileage then, in the mornings my ride would run rough till it warmed up I thought it may have a need for a thermostat but when I pulled the driver-side front cylinder plug it looked like this( see pictures) I was pist, It has been about a yr. but I would think the plug would last longer. So I went to a auto shop and got new plugs auto light or something got back popped one in and started the second one and lo and behold it looked pretty good and so did the other ones so Im thinking to myself defective plug or that thermostat needs to be replaced? what do you guys think I got pretty good action out of the bosh +2 plugs and I have feeling that it may be the thermostat possibly not working proper? see that dark spot it is a chip or burned out spot on the plug I will see how my ride runs in the morning that is when it was running rough.

 

I would toss the Bosch junk and put some AC Delco or NGK double platinum plugs in (or spring for the laser iridium - the ones with the platinum ground tip). Well... That plug recommendation is based off of the CPI engines or newer... If you are running TBI or carb'd, then the general AC Delco plugs or NGK v-groove plugs will work just fine as well and are MUCH cheaper.

I can't really see your pictures too well since the camera didn't ever focus on the plug itself, but it doesn't look too bad. A light brown color is what you want on the plugs.

 

why do you say that? are iridium or even platinum plugs going to waste in a TBI engine? if so, why? i was going to do plugs soon in my 92 s10 tbi and was going to use delco platinums.