My timing belt broke about a year and a half ago, and it caused one of the valves to chip. I'm assuming that's what caused it anyways, since it happened at the same time.

Today I was just driving along on the highway in 5th, not revving it super high or anything. The cel came on and started flashing, and I noticed the exhaust sound changed and it sounded funny. I got off at my exit and it was running weak. At first I thought the timing belt had slipped a tooth on the exhaust cam or something. Checked the codes, it gives P0302 for misfire in cyl#2 and P1399 for random misfire. Got home, and ran a compression test and cyl#2 has zero compression. The other cylinders seem abnormally low also, between 120-140. I'll squirt some oil in them or something and run the test again to see if it's the rings, but does anyone know what causes that to happen "randomly"?

Car has 123k miles. 99 LS.

 

I know P0300 is random misfire, I've never seen a P1399 for random misfire...? Well, obviously you've got a major problem in the #2 hole if it's got no compression whatsoever. If you're gonna tear it down to check the carnage, you can check the cam timing before taking it apart, that may be the cause of the rest of the cylinders reading low. One way or another, the head's gonna have to come off at least.

 

I checked the cams, they're fine. I found a used head for $100, probably will go pick it up tomorrow and throw it on there.

 

Did you replace all of the valves after the timing belt rupture?

 

Swapped in a different head altogether. Valves and all.

 

try to use someone elses sparkplug wires. and try different spark plugs after. see if you still get the problem. as for the low comp. maybe you blew a ring and your getting blow by. maybe that's it. change your oil out and while your draining it, observe to see if your oil is a way darker than it should be. also while your draining the oil, get a magnet or something and put it in the path of the draining oil. the magnet will collect metallic shavings if any of the rings have collapse on you. keep us updated.

 

I'm thinking of putting new rings in it tomorrow if I can get a hold of some. I'll let you guys know what happens. I think when it was Turbo'd it might have screwed up some of the internals but I'm not sure.