I mis-downshifted from third to second the other night (over-rev), and the next day, after an hour of a/c hot drive, the car felt a bit slower and started idling rough, and the CEL consequently came on. Luckily I was close to my house and made it home. I hope I didn't do any permanent damage from the mis-shift.

My engine mods:

IK24 Iridium plugs
Hondata heat gasket
Mugen termostat/fan switch/rad cap

btw: I didn't notice any odd exhaust smell. The rough idle was similar to when I forgot to plug in an ignition cable after I installed the plugs, only less rough. The motor just shakes back and forth. I think some kind of mis-firing is occuring.

Help!

 

Don't drive it anymore.

Transport it straight to dealer.

No chance it will get better on it's own.

Expect the worst too. (Like bent valves)

 

yeah, I'm worried about the bent valves...

 

The valve train is most likely hosed. Open your wallet W I D E. If you continue to run the engine with bent valves, more damage will occur that is even more $ to fix. If your lucky, the pistons won't have any holes in them. Consider yourself lucky if replacing the valves is the only thing you have to do.

 

looks like I'll be taking it to the dealer and bracing myself for the WCS...

 

Just got back from the dealer, and they did the plug recall, and the idle supposedly got a bit more stable. After doing a compression/leak down test, they didnt' find any evidence for bent valves. So for now, hopefully, a valve adjustment will take care of the problem (fingers crossed).

 

update:

They did the valve adjustment, but the intake valves for cylinder one and four have receded into the head, so they weren't able to measure the gap clearence. They suggested to me that I should take apart the head at a machine shop. Only problem is, the labor will be almost a thousand dollars. Other than that I could drive around with that problem. Only thing is, there may be more serious problems down the line.

Anybody know what damage the recessed valves can do?

Argh...

 

Just got back from the dealer, and the car is as rough as ever, even after the plug change and the valve adjustment. I just wasted $135. The compression test proved that cylinders 1 and 4 do have some kind of defect, as the numbers for those came out to be 180 (not sure of the units). #2 and #4 cylinders were normal at 220.

Looks like I'll have to take it into Alaniz and open the head, get new valves (and/or retainers/valve springs), and another valve adjustment.

Moral of this story: Downshift with care, meticulous care...

 

The real moral of the story is to use your brakes to slow the car, pads are cheap, clutches are not, valves definitely are expensive.

Other than that I'd say to trade your car in. Make sure it is raining.

 

Please ask you dealer which CEL codes were posted by OBD-II (P0301-P0304 or others?). Damage may have occurred when "I forgot to plug in an ignition cable".
Missing a downshift is very easy in this car....push in the clutch to save your ass!

Utah

P.S. Fishfryer...if you can't say anything constructive go back to the Corvette board and maybe they can help you fix your car. Flaming here is frowned upon.