Try checking the vacuum lines as well, those have a tendency to break often and I'm not sure how large of an impact a broken one would have as far as causing it to run that rough, but I do know from experience what a vacuum leak can do to the engine so if one is completely shattered or just popped off, it could be causing some problems. I've also heard of worn out engine speed sensors being the culprit of having a hard time getting it to start so you might check or replace that as well.

 

Hi all,

Just wanted to give an update on my situation. I ended up replacing the spark plugs (the old ones didn't look that bad to me) and the wires (two of the old ones had broken connectors on the coil pack side). At this point, the engine sounded better to me than it did the other day. I don't think it's making the same sputtering sound I heard before, so I think it might have helped!

Unfortunately, I now hear a "gravelly" sound like an idling tractor trailer. The sound is present no matter what gear I'm in. I think this sound was probably there before, but I didn't really notice on top of the earlier sputtering sound. I also tried replacing the coil pack as suggested in this thread but it made no noticeable difference, so I put back the original one.

One interesting thing we figured out is that the gravelly/tractor trailer sound does NOT change in pitch/speed/intensity with the engine speed. This leads me to think it's something like a bad bearing in one of the gears that the serpentine belt passes through and that the engine itself is ok. Does this sound like a reasonable assessment?

Thanks,
-Allen

 

I could be wrong, but the gravelly sound could be a worn cam chain tensioner. I'm not all to familiar with the finer workings of engines as far as diagnosing things based off sounds, but I think your guess that a bearing or something on one of the accessories driven by the serpentine belt is shot is reasonable, and unless I've got my head in all the wrong places about the cam chain tensioner, it's more or less a bearing as well so it could just as well be that too. I have a gravelly/diesel sound coming from my motor too though, but it only happens in first gear, after I shift to second the sound goes away completely and some people have told me it could be a worn cam chain tensioner, others have told me that's just the sound a 2.8 makes so I'm not positive on my claims.

 

I'm surprised you didnt look at the PS pump.. if it went dry and then bad, it could've killed the engine.