I've been throwing a lean code for some time and had my spark plugs changed about 3 wks to a month ago. Decided to pull the plugs and check them out, and they seemed pretty sooty. The ones in valves 1&2 were real bad, and 3&4 weren't as bad, but still somewhat. Is it the not burning of the fuel that's creating both these problems? or? Just trying to figure things out step by step.....the plugs weren't gapped correctly, so I got some new ones and gapped them to .028.

The plugs I used, because i couldn't get my hands on the ones I wanted, were the NGK BKR6E (the sames that were used when the plugs were changed the first time). My car's been chipped and some other performance mods added, and I was wanting to get the NGK BKR7E plugs. Will the 7 plugs help out w/ the lean/sooty plugs? or was it more the bad gapping? When I got the new plugs, they were gapped at like .035 before I re-gapped them.

 

So were the plugs a really light grey or dark almost black? A lean code is usually caused by a vac leak or bay primary o2 sensor.

Those 6's will be fine if the gap is correct.

 

They were black, definitely not gray.....

 

That would mean they were rich. Deff not burning the fuel with the giant gap. Just reset the code and see if the new plugs and gap fix the problem.

 

My next question, however, would be how are they being rich while I'm throwing a lean code? I reset codes at the time they were put in (and have reset it for the ones i just put in as well) and the lean code keeps coming up. I already have pulled another code and gone into limp mode since re-doing the plugs (but haven't been able to check the code yet). I'd just think I was either being lean, or being rich, not both (?)

 

The o2 is reading lean and its adding in more fuel than you need, thus rich in the cyl and lean at the ecu. You either have a vac leak at the fpr, bad o2 sensor, or even a bad exhaust leak before the primary o2. If its the p1128 i believe the code is, i would consider swapping out the o2. you can also try cleaning the maf just incase

 

After we did the spark plugs the first time, we also swapped out both O2 sensors, and the MAF was replaced before the spark plugs, and cleaned right before the O2 sensors. I've looked over everything I can see and can't find any vac leaks, and my boost gauge reads 21mmhg at idle (and is T'd off at the FPR). Is there one of these that is more likely to have refailed than the others or a way to look at it?

Also, thanks for the explanation of the rich/lean code/plugs, makes perfect sense now

 

Check for an exhaust leak and move the line for the gauge to the dv so the fpr has its own vac source.

 

where can u move the gauge to in respect to the DV? off the small top nipple? Is it not supposed to T off the FPR?

 

I was wondering about the connection to the DV as well. The hose that leads to the top of the DV is a tad bit bigger, do i just need to run some sort of hose size reducer for it to much it up w/ the hose size for my gauge, or?