RDnomorecobra

Was at NJMP this weekend with NASA, 3rd session today (2nd day) I noticed a little vibration, car seemed to be making less power, looked down and saw a slow blinking check engine light. Came in and put it right on the trailer. I could tell the idle didn't sound right but wasn't real obvious to anyone else.

What do you think? I had an extra quart of oil in it like usual. Checked it this morning and level was fine, catch can had maybe a few ounces in it and started empty yesterday which is normal. No leaks anywhere.

SunnydayDILYSI

Hard to tell from just that info, but kind of sounds like one of the pistons is not getting fire.

ErnieN85

check the plug wire real close......sometimes they come off

VetteDrmr

Flashing check engine light is indication of a persistent misfire. Check your PCM codes (P030x) and see what shows up. Burnt wire, overheated/dead coil, etc.

HTH, and have a good one,
Mike

RDnomorecobra

will check a few basics this morning, then it's off to Phoenix. A few posts indicate could be a valve spring and resultant badness. Hopefully not too bad.

taken19

I had something similar a while back and it was a broken rocker bolt. You would see the same with a broken valve spring. Pull the engine codes and it will give you a clue. Also, check plug wires and remove valve covers for inspection. That will cover 90% of the potential problems. No need to send the car to someone else for a simple fix...

mgarfias

Could have lost an injector too.

PA Z06

had similar issue, had already replaced valve springs, ended up being a bad wire

AverageVetteNut

sounds like when I lost spark and it was the wires...plural.

Hope it's nothing too bad.

RapidC84B

Pull the valve covers and check the rocker arms and springs before you fire it up again. If a valve drops it goes from an easy repair to an engine replacement.

harrydirty

Before you do all the hard stuff, check to make sure one of your hydrocarbon absorption mats has not come loose inside your intake. I had one come loose during a track day and check engine light came on and the engine stumbled badly, then would run, but not with full gusto. Thought it was a MAF sensor (codes indicated) but stumped me until Rich from Abel Chevrolet suggested the loose mat(s).

Good luck on the fix.

froggy47

First get the codes.

mgarfias

Eh. I'd go one further, get a scan tool on it, and see which cylinders are tossing missfire codes. If its all of them, then you know its something systemic. If its less than that, it narrows down the possibilities.

I should add that mine did this earlier this year after not being driven for awhile: bad bad bad misfire. I figured bad gas, ran it out, refilled and cleared codes. Still there. Kept thinking it was bad gas still around until I finally realized it wasn't clearing up. Scanned, found 3 cylinders were out. Verified spark on each, and then started pulling injectors. Figured 3 were bad, found a "new" set (40k miles, supposedly good) for $75, swapped them in, and the misfires went away.

froggy47

Hmmmm, guess injectors like to be exercised on a regular basis, good to know.

Good to use a scan tool if you have one.

I said codes first as they are free on the c5, need a tool for c6.

The codes actually pin it down to a specific cylinder, I had a ck engine light & cyl #5 (c5 code 0355 IIRC) last Sunday at an event.

Found slight arcing, I may put wires in if it comes back.

mgarfias

Huh, I didn't see a specific cylinder code when mine was acting dumb.

I do still have a bit of a misfire. I should probably pop the valve covers and at least think about swapping springs. But I tell myself that if I do that much, I might as well go all the way and pull the heads and replace em with something ported. And a cam.

RDnomorecobra

rocker bolt in #3 came loose, not broken. threads were good, reassembled and runs good. checked all others and they were fine. weird. I bought the car about 5k miles ago and no indication that the prior owner had done any work in there and maybe never torqued it down properly. what would cause it to just come loose?

froggy47

Maybe was just built that way, stuff happens, glad you are fixed.

VetteDrmr

Roger that!

RapidC84B

I'd pull them all and put a dab of blue loctite on them. Torque to 22 ft/lbs, turn engine over a couple times, torque again.

froggy47

Just out of curiosity, does loctite specify that the fastener be free from oil (clean & dry) when applied.

I always do it that way, but I never have used it inside the engine.

Not that it's a bad idea, just curious.