I had a misfire for a while and was throwing p0300 via my predator... the was backfiring and idling really rough... after monkeying around with the plug wires, coil packs, and several sparkplugs, I decided to take a look under the valve cover. Once I got them off I clearly saw what the problem was - cylinder 6's pushrod was bent - when I pulled most of the pushrod out I saw that the little guy also snapped about 2 inches from the bead, took me a while to fish the damn piece from the cylinder head, but once I put in a new rod and reassembled everything the car runs like a champ! It's good to be back on 8 cylinders.

Just thought I'd share that, I'm no mechanic and it was really easy to fix this up. Thanks to those that have posted stuff about misfires, if it wasn't for this site my red dragon would still be puttin around on 7.

 

HOLY CRAP!!! [/Peter Boyle]

 

Wow!!!

 

that doesnt make me feel good about my p0300.

 

Is your engine rattling at idle and backfiring when letting off the gas in gear? mine was doing that, and the wierd thing about it was I couldn't hear anything unusual when placing a rubber hose on the valve cover and into my ear - thought there would be clanging metal pieces or something. The thing that really gave it away was pouring water on my each header pipe coming out of the head - number 6 pipe didn't boil up the water like the other pipes did, so that told me nothing was coming out of the exhuast valve indicating the pushrod fault.

If you're cammed it can throw a false p0300 too so it may be nothing.

 

i thought about it, and mine is only @ low rpm on cold starts, once it warms up it seems to go away...obviously not symptoms of a broken/bent pushrod. yeah my cam is pretty healthy, but a tech 2 showed slight misfires on 6 of 8 cylinders last week, now i replaced the wires and am gonna check it again on teh tech 2 come monday.

 

Did you check your other pushrods as well ? I bent 4 or 5 of mine a few months ago and had a misfire at higher rpms. Yours is bent a lot worse then any of mine were so if you didn't check them all I would check them.

 

How hard is it to change pushrods???

 

http://www.ls1howto.com/index.php?article=21