Reading my spark plugs... Running Lean? EVAP?

[1997XLTRollover]

Hey guys as a lot of you know my freshly built 96 5.0 (306) has been getting about 10 mpg and I'm trying to figure out why. After 2k miles or so of run time now this is what my plugs look like. Is this enough miles to give the nice burnt color I should see or do you guys think my truck could be running a bit lean?

I just got a CE light this past weekend for an EVAP leak and was wondering if maybe this leak is causing me to have a vacuum leak and causing a lean condition.

 

[1997XLTRollover]

Bump. Anybody?

 

[koda2000]

Yikes, you're running way lean. The insulator on a normal plug should be tan, not bright white. Any sort of unmonitored air leak will cause your engine to run lean. I surprised you don't also have lean codes (P171/0174) with those plugs. 2K is plenty of miles to reach a normal plug color.

 

[1997XLTRollover]

Ok that was my thought too. So maybe I'm finally getting somewhere. The truck runs ok but does sound "airy" probably because it's running lean and can't pull more than 13 mpg highway. I was also wondering if the timing was off.

I think timing being off can cause this too? I got a cigar and blew the smoke through the intake and I cannot find any leaks. The only code my truck is throwing is an EVAP leak code. Is there anything else I can do to check this thing out? I want to hammer down if I'm dealing with a timing issue or mixture issue. I don't think I put the timing chain and gears on wrong but you never know.

BTW this is on a freshly built stock 306 (with torque monster headers) so it's possible I screwed something up, although I'd like to think I didn't. Maybe I'll pull a few more plugs but I'm betting they all look the same.

The weird part is the truck runs ok. Not rough, pulls all the way to redline, driveability is fine etc. Might be a bit underpowered but it seems to run fine, so being this lean I would think I would have a massive air leak somewhere which is why I'm wondering if it's a timing problem especially since I have no lean codes.