tech2

maybe the previous owner changed.

BGrahovac

I just checked the fuel trims
At idle:
Short term bank 1 fluctuates between 0 and negative 3
​​short term bank 2 goes between negative 2 and negative 3
long term bank 1 is 101
long term bank 2 is 12

When RPM brought to 2500
short term B1 goes as high as 2
Short term B2 goes as high as 3
Long term B1 is 8
Long term B2 is 7

Can you break this down for ne and tell me what I'm seeing here? Thanks

BGrahovac

After running for a few minutes the fuel trims at idle are now:
ST B1 0-3
ST B2 1-3
​​​​​LT B1 5
LT B2 7

2500 RPM
ST B1 negative 1 to 5
ST B2 0-5
LT B1 5
LT B2 5

mountainmanjoe

these are nonsense. Gotta wait for the engine to warm up and go "closed loop"

mountainmanjoe

These are more or less healthy. Slightly on the rich side.
I guess you just had a timing issue.

BGrahovac

LT B1 was supposed to be 10 not 101. I fat fingered it. Engine temperature at 210 and it is in closed loop

mountainmanjoe

ok so it starts high and then settles down a bit. LT trims could be lower.
Is the air filter clean? Try cleaning off the MAF sensor with some spray cleaner.

BGrahovac

Air filter is clean and new. Just installed a couple days ago. I will try cleaning the mass air flow and see if that does anything

BGrahovac

Cleaned the mass air flow and no change in fuel trim.

Hete js something odd though....if i monitor nisfires on the scanner and slowly bring the rpm up to 2500, there are no misfires BUT if I rev the engine slightly, there are some misfires on 1,2,6, 8 and sometimes 7. Along with this there is a "sucking" sound when revving the gas slightly. I have the doghouse off and I swear I can hear a faint vacuum leak at idle. I've sprayed a little brake clean around and no change in rpm. I just can't seem to find it.
any ideas about these issues?

mountainmanjoe

smoke test
or follow the sucking sound with a mechanics stethoscope