I have a 91 Z28, 5.0/5-speed, purchased last fall. As far as I can tell, the only modification significant to starting/running is a MSD ignition module.
Until now, the car has started and ran great, except that 6 months ago I installed a new fuel regulator diaphragm (the old one actually had a hole in it!) and it ran perfectly again after that.
1 month ago all of a sudden it wouldn't start one afternoon at work
. Long story short, I've found that it will start 7-10 times in a row, and then for no apparent reason it won't start. I've installed a fuel pressure gauge and have verified that pressure is good (42 to prior to starting even if it fails to start, 35 at idle when it starts, pressure rises with accelerator pressure).
I've been blaming it on bad fuel, and attempted this week to run the fuel out of it. The cars runs perfectly though once started, but on this latest attempt to use up the fuel I found that after some time, it would no longer idle. It ran great as long as the rpm's stayed up above 1500 or so, but if I let it idle it would immediately die.
I also found that while being towed
it would start immediately when I let out the clutch in 3rd/4th gear. In fact I was able to get it back home under its own power as long as I kept the rpm up. (that was some tricky clutch/brake/accelerator action) Once in the driveway it had to be pushed into the garage because it would not start again.
Thoughts on this problem please!