Just so you know, this is not on my procharged 383, this is is just a 330 HO GM crate motor, with a tpi setup on it with richmond 6-speed.

Here's my problem. Over the course of about 3 months now, when I crank my corvette after it has been sitting (about 4 hours minimum.)

Icrank it, it sounds normal, idles perfect. I start taking off, just moderate acceleration, and you can actually feel one (or more) cylinders not firing. It is like "cutting out", the more you try to "gas" it, the worse it is, if you floor it, it bucks, jumps and does accel, but not smooth at all. ALTHOUGH, if you hold the rpms in gear say run out each 1st, 2nd gear.... by just about 1/4 throttle, it will let you go smoothly all the way to 4k or more without any missing, but when you try to accel quicker, it cuts out.

I thought for sure it was a plug wire arching, so I put a new set of delco wires on, new dist cap, rotor button while I was at it.... I even put dielectric grease on both ends of the plug boots... just to be sure. I removed all the plugs (which are about 7 months old) and inspected them... the all look white and burning clean. I thought it could be an injector leaking down, but figured one plug would atleast look a lil wet, black.... but all 8 plugs looked exactly the same. I thought I may even have coolant leaking into one of the cylinders... but since its been doing it for 3 months or so... you'd think I'd be missing coolant. The coolant level is fine.

What doesn't make sense, is that once the vehicle warms up... to 150 degress or so, or about 3-4 minutes of driving, it drives just fine... it does slowly get better though, on the rough accel. until its warm... then drives normal. Unless you let it sit say from morning till I go to lunch @ work, or overnite to go to work the next day.

Any ideas on what to check? I have not checked fuel pressure leakdown because I dont know a good way to isolate individual cylinders.... and besides, the plugs look fine, and there are no raw fuel smells, or black smoke when 1st cranked, it also idles fine when 1st cranked, just doesnt accelerate "quickly" very well.

Maybe someone has had this problem, and can help me pinpoint it quickly. I am thinking a bad coil??? or spark control module.....Any Ideas ????

 

Without an adjustable spark checker, it's hard to tell. But, it sounds like weak spark or arching inside distributor cap. Are the plug wires seperated? I have seen crossfire happen. Have you tried a vacuum gauge on manifold vacuum to see if there is any flucuation when the missing occurs? Maybe a broke valve spring?

 

is this opti spark system ?i dont know how many miles on the new plugs but they should not be white. its sounds like ign. ya need test eguipment

 

It's a L98 Tuned Port. [8D]

 

My L98 did the same thing once, turned out to be a leaking intake manifold gasket. Mine was leaking into the lifter galley. Sealed up a little when it got warm.

 

I had starting problem when cold and misfired. My problem was a faulty connector on the coolant sensor. If your coolant sensor is not right it will cause the ECM to not give the right fuel mixture. It made me a believer I started mine day before yesterday at 20 degress and engine excellarated fine.