I bought a 2000 corvette about a month ago from a local corvette dealer. It ran strong, though I did notice a slight ticking coming from the passenger side. had no codes of any kind. couple of days ago I took it for a spin and I got into it in first gear. got up to around 3500 to 4000 rpms. then i notice the ticking turned into a tapping noise. the check engine light starting flashing. had it towed to the dealer and they said that 3 and 4 cylinders were misfiring. they said start with new plugs and wires. so i did. still misfiring. checked the ohms on the fuel injectors. they were all the same. thought maybe coils. so i check the ohms there and came up with 104, one was 97 and one of the others was 117. i checked the plugs on 3 and 4. still had gas on them and looked like they hadn't been fired. Any more thoughts? by the way the ticking and tapping had stopped. and only code current is P0300 and it had a history.

Thanks

 

You might want to check the valve springs. Are the coils OEM? I should hope that the dealership will not charge you for the plugs and wires since their replacement did not solve the problem.

 

Dave01, I did the plugs myself. dealer wanted $550 for the job. last night i let it idle and check the coils with a timing light and all was good. plugged the code reader in and erased the current P0300 code. after a minute or two it came back. gonna check the gap on plugs again tomorrow. i think .040 is the correct gap. also bought a pressure gauge so i can check each cylinder. im gonna take your advice and open the valve covers and check the springs. the dealer said number 3 and 4 cylinders were misfiring. what would cause opposite cylinders to go at the same time? what are symptoms of a bent rod. could it be head gasket? or would i get more codes if it were gasket? a friend said i may have spun the motor and valves are out of position. if that were the case then it wouldnt idle at all right? now it is idling rough. uhgg! id love to fix it myself and post it.

Thanks for the help

Love this forum

 

Whoa,.....stop the music.....

" a friend said i may have spun the motor and valves are out of position"

You want to explain this?

The only way your valves would get out of time/position with your crank/pistons
is if you dismantled your timing gear assembly and "spun"/rotated the cam or crank,
then reassembled the engine. You didn't do that now, did ya?
I didn't think so.

O.K., back up and let's start over.
Make sure all the mech stuff is right.
Check your compression first.
Both wet and dry test.
Next, I would go to the rockers for the valves of 3 and 4.
Check them for propper adjustment.

If everything mech checks out, the prob is elec. or fuel delivery.

3 and 4 being the culprits, makes me ponder the fact that they are next to each other on the dist. cap. Hmmmmm, I wonder,.....
(Heck, I don't even know if a 2000 Vette even has a dist. cap. LOL But if it does, ya might wanna clean it up real good and take a real close look at it, maybe even replace it.)

 

c3 starship, i think i said it wrong then. i think he was saying the cam my be worn and i reved it up hi enough to that the cam got out of sync? not quit sure how that would happen. i talked to a chevy mech. he said basically what most have said, probably a busted valve spring or bent rod. it used to make a ticking noise that i read was normal. after the higher rpms i put on it, it turned to a tapping noise on the was home. very audible. now it doesnt make any of those noises. just idles rough. p0300 code.

thanks for the info im still hunting it down

 

Naw, it ain't gonna go out of syc.
Apparently you have the same prob in 2 cyl.
Collapsed lifter(s) is another thought I have.

What's the comp, (check all cyl for comparison)?
Your valves adjusted?
It's all speculation until you check these.

 

i would put a spark plug tester on cylinder 3 and check for spark
then i would do the same for cylinder 4
if both get spark
u need to put a injector node light on cylinder 3 and check for it to flash
then do the same for 4
then i would get into compressor test
but if the noise is loud or never goes away
i may go straight to looking at springs
u need to pin point which side u hear the noise from more
and remove that side rocker cover
but a compress test will also help u pin point the problem

 

.....all good advice.

 

Good call! Compression check on number 3 cyclinder was shot. got good psi on number 4. oil is clear. havent lost any coolant. valve spring or bent rod? what are the chances that the valve dropped? like i said before, i had a slight ticking when i bought it. after the check engine light came on the ticking turned to a tapping. but it hasnt done it since. i havent drove it. but i did idle it while trouble shooting it. gonna open up the valve cover and take a look tomorrow. I got a dvd repair maual coming in the mail.

Thanks again guys

 

No. 3 could be a hung or burned valve. Since there was no mention of backfire, I suspect the exhaust valve. Pull the valve covers on both sides, ya still have an issue w/No. 4., right?