I've varied my timing from the recommended 6 btdc to 12 btdc. It runs smoother the further I advance it but the best running timming makes her ping. Reading the service manual they say I should have 34-39psi fuel pressure, I've only got 28 with vacuum.What kind of reading do you have on yours without vacuum. Also wondering if my cat is creating a backpressure issue. Thanks.

 

I have about 37 psi with the vac unplugged. Listen to your exhaust, is it making a hissing sound if so I would suspect a clogged cat. Have you tried un plugging your sparkplug wiresone at a time to see if you have a cylinder misfiring? Have you done a compression test on all eight cylinders?

 

Another pressure reference in the article, page 6, 3rd column, near the bottom:

below 35 psi, you get poor air/fuel mix, and idle and driveability problems. Is this the problem???

 

1990 with same problems should I try the same fixes or is the cars different? Can only get about 12 degrees advance before engine stumbles badly?

 

On L98 engines the timing should be set at 6 degrees BTDC with the timing set connector unplugged. The timing set connector is located beside the distributor on the passengers side, it's a single, (brown and black I think) wire coming out ofa wiring harness. Be sure to reconnect it after the timing is set.

 

Well guys, the saga comes to an end. Found the consolidated ground on the drivers side head had a nut that was close to vibrating off, tough to see, but still visible. Appreciate all of the good advice and a special thanks to rshiver.

 

Congratulations man, glad you finally got it, now go and enjoy your Vette.

Cheers

 

I told you !!! Wouldn't listen to me tho', huh? Noooooooooooooo... Vacuum leak, huh? Where did you get that idea anyway? Comic book? Horoscope? Psychic hotline???

 

....THANK GOD THATS OVER WITH[&:]

 

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