Running lean

[SHO13]

Pulled my plugs, they are pretty grey. I'll clean my MAF tonight (no-residue brake cleaner ok?). Is there anything better to clean it with?

I'll also check for vacuum leaks. If I attach a vacuum gauge to the intake manifiold, what kind of numbers should I see at idle?

I seem to have very very small leaks on the intake manifold rubber seals. There are slightly dirty/oily film spots where the rubber joints are. These have built up over the course of 50K miles. I thought the intake was under negative pressure. Does it ever get slightly positively pressurized?

I also have dirty/oily vent spots around the valve cover bolt seals.

Could this be causing the lean condition? Is there anything besides a vacuum leak or out of whack MAF that causes this?

Thanks,

 

[Black '93]

Use electrical safe cleaner and be vwery careful w/ the hair thin wire thats in there. The dirty spots by the runners probably means that there was a tiny tiny leak for so long that it got a bit dirty just like the inside of the intake. The spots around the valve cover seals means you need to replace them. I wouldn't reccomend trying to tighten them in case they are already over torqued. The vavle cover bolt seals wouldn't affect the lean condition unless they were really really bad and the motor would probably be spilling oil.. I'd replace the valve cover and intake gaskets along with all the vacuum hoses on the intake. A number of things could cause the lean condition though.. Including bad vacuum hoses or intake leaks

 

[SHOZ123]

What's the fuel pressure like?

 

[SHO13]

Appreciate the help,

I haven't checked the fuel pressure yet. I haven't had any problems with loss of power at WOT. She seems to run pretty strong, just really lean. I'll pick up some electrical contact cleaner. How long do you think it will take for the plugs to change colors back to tan? 100 miles or so?

Thanks

 

[SHOtime2511]

how old are your o2's?

 

[SHO13]

O2's are Bosch and approximately 5 yrs old. If I remember correctly, she has always ran a bit lean.

Is there a baseline vacuum reading for the manifold at idle?

Are there any writeups on the Tweecer, what exactly does it do? Does it reprogram your computer?

Thanks,