bmartini

the car was running fine until one morning i started it and it was making a terrible noise. my CEL indicated a misfire in cylinder #6. I replaced the spark plug and ingnition coil and the light is gone and there are no codes.

But the symptoms are still there: car has a very loud rattling from inside the engine, no power, shudders and shakes.

Ideas?

dresler

Cracked cylinder, or IMS at worst. At best..... dunno.

Have it flatbedded to your indy, in case it is the worst.

bmartini

whats an IMS? the noise is coming from the left (US drivers) side of the engine.

dresler

Intermediate shaft, bearing, and timing chain. I really don't know if this is it, and I don't want to alarm you, but you should think about not running the engine until a mechanic looks at it just in in case. If you search IMS on this forum, you will not sleep tonight. So, don't.

Maybe the muffler baffle came loose, you have a broken cat, or something like that, but best to be safe.
Good Luck!

dresler

And I just remembered, a couple of folks in this 996 forum had an engine rattling noise that mysteriously disappeared. It was about a month ago, so if you use the advanced search with the word "engine," you should find it.

Just don't read any topics on oil, none of us know squat about that.

bmartini

thanks for the posts man. what is strange is that i drove it at night and it was great. parked it overnight. and in the morning i get that terrible noise and the misfire. never had an oil pressure or overheating issue. how could this happen?

redridge

sorry to hear this..... can you describe the noise further? GL with this.

Svoruz

Had a similar problem after I replaced my coolant tank. The problem was found to be the drain tube from the coolant tank was placed right over cylinder 6 and when it would drip onto the coil pack it would misfire and the CEL would come on. Re-routed the drain tube and haven't had a problem since.
Good luck.

dresler

So, what was it???

1999Porsche911

Must have been one hell of a long drain tube to reach all the way to the other side of the engine?

I'm sure you ment cylinder 1 or 2?

Chuck Jones

Hate to say this...but it sound so typical of an intermediate shaft failure. They just seem to go for no reason....the car may be idling and run great one minute then rattle like a coffee can full of rocks the next. That noise won't go away if it's IMS failure. It's a catastrophic failure that requires an engine rebuild. I sincerely hope not...but ......

bmartini

new engine on the way :-(

Mother

Glad to hear new engine on way. Was your car under warrenty and where did you purchase engine?

bmartini

no, bought it at a porsche salvage yard 80 miles from my house. seller says it's just been rebuilt with a warranty. i haven't picked it up yet, he wants my core first. i hope to get the old motor out by wenesday and the new one in by the end of the week.

no warranty. engine was nearly $6k. doing the labor myself.

i figure i'll change the tranny fluid while i'm at it, does anyone know what exact fluid i need to buy for a tiptronic?

OT: also curious about a good place to buy the updated rear lights, dealer wants almost 800 bucks.

joes c4 cab

Yuck - sorry to hear that. Same thing happened to mine - sat in the garage over the X-mas holiday, and 4 days later I got the same thing you did, followed by lots of smoke. I knew immediately.

Better get some sort of warranty with that motor!

Best of luck.