Hey guys;

I'm helping a buddy, he's got an LG4, with an auto. Non-cc Q-jet. Rebuilt tag on the q-jet.

He just bought the car, history is unknown. No modifications, bone stock- covered in dust/crud and untouched.

Car was stalling at first. Found a vacuum leak between intake manifold nipple and trans modulator.


Put new plugs in it, installed an MSD spring/weight kit, and drove it around the block a few times. Pulled the plugs, rest of the 7 look great, and #3 is carboned. I pulled the valve cover and watched the rocker arms move - no problems there. I disconnected the plug wire, and put in a spare plug, and held it against the exh manifold - good spark.

When driving the car, it's down on power, and idle vacuum is ~15". That seems low for a stock 305 to me?
Checked compression, 180 across the board. Beautiful.

Checked timing. Seems to enjoy using ~40* timing to idle?? I verified the timing with a piston stop.

Driving it around it seems to be pinging under load - to me it seems like it's missing on one hole.



My first thought is an intake manifold gasket leak between valley and #3 cylinder.

Any alternative thoughts i'm missing that might explain either;

- low vacuum
- carboned #3 cylinder
- loss of power
- massive timing to keep it running

??


Thanks