[pcking]

OK, so as promised, I got under the good yesterday... long story short, its all better...

So, if I told you that worn engine mounts were the issue what would you say? :-)

OK, so I grabbed the wife's car (Nissan Rogue - I so _HATE_ this car, esp. after driving the BMW) and ran over to Autozone and grabbed a can of the CRC brand MAF cleaner. Shot back home and started taking apart the air intake so I could get to the MAF.

As I started loosening the MAF, I noted that the whole pipe it was mounted to seemed to be quite loose. Feeling around underneath, I could feel that the intake tube has separated at the silicon hose joint. So I removed the entire intake housing and sure enough it the two pipes were no longer connected. Upon close inspection, I noticed that one of the clamps that holds it in place had failed.

At 6'5" and 265 lbs I do have a tendency to overtighten things (they usually don't feel tight until I strip them) which is why I use a torque wrench as often as I can. Of course an air intake clamp is not one of those places, so I suspect the clamp was VERY tight.

After I cleaned the MAF and reassembled the air cleaner housing, I started the car. It stumbled just for a moment and then proceeded to settle to idle at about 700 RPM (as usual). After a few minutes for warm-up I had my son get in the car and rev the engine while I looked around under the hood. To my surprise, the engine exhibited a TON of back and forth movement or more like a few degrees of rotation

This also explains why my upgraded exhaust required an adjustment after it started rattling recently. The engine must really twist under full power acceleration, esp since the mounts have >165K miles on them. This twist put stress on the clamp holding to intake hoses together and eventually fatigued and broke the clamp. One end of the pipe is attached to the engine and the other to the intake housing, which is bolted to the body. Same thing with the exhaust - one end connected to the turbo outlet and the other hangs off the body. Twist the motor back and forth over and over and things will come apart eventually...

So, while I will be adding a new air filter and swapping the plugs, I do not need to replace either fuel pump at this time. I'll also be looking into getting some poly engine mounts to replace the tired OE units with something a bit more robust.

Thanks to all those that replied / offered input. Very glad to be back on the road.