Passat V6 30V Misfire Cyl 3, runs rough, no power.

[CommieHunter]

So I have a 2001 B5.5 Passat, 5sp, V6 30v 2.8L.

A while ago I got a CEL, code says it's O2 sensor, Bank 2, sensor 1. I let it go since it didn't seem to be affecting the car. Two months later, CEL still on, the car starts to shudder when I load the engine. It won't run right under 1000RPM, won't give me anything under 2000rpm.

So I have the code read, same O2 sensor, now it says Cyl 3 misfire also. So I decide to do what I should have done, I replace the plugs and give it a new O2 sensor. It drives fine after that, smoother but still not enough power, next morning the CEL is off. Day after it comes back on, misfire Cyl 3. Now it's only showing Misfire Cyl 3 code, but the engine stutters and coughs if I try to accelerate faster than old Mrs. McGrady, and it won't go up the hill near my house under 2200rpm.

Any ideas?

[CommieHunter]

So the plugs have been replaced and I ran fuel injector cleaner through it with no results. Do I have a bad coil that needs to be replaced?

[02GLXWag6stk]

Without a Vag.com printout of faults with the pertinent DTC's, one is pissing
in the wind!

Good tho that you changed the #3 spark plug to eliminate that at least.

IF you have over 100K miles, good to invest anyway in a new Bosch set of ignition wires.

Could be the camshaft sensor in that cylinder bank; ignition coil pack rarely goes bad in 2.8L.

Doesn't make sense to throw $ at a problem unless you get a printout of DTC's from Vag.com

HTH

[kfzmeister]

So the plugs have been replaced and I ran fuel injector cleaner through it with no results. Do I have a bad coil that needs to be replaced?

Easy check: pull up fuel rail and swap #3 injector with another existing one (careful since fuel system is under pressure). Then start car. Erase codes. Does misfire code now appear where injector was moved to???

[Sickblueb5]

Hey buddy before you start pulling injectors, Swap your plug wires around.. reset the check engine light. And wait for it to come on again so you can read whats going on.. Ive had this problem and the culprit was ORIGINAL SPARK PLUG WIRES @160K miles.. replaced the wires and the car was smooth like butter.

[CommieHunter]

Thanks for the tips! Here's where I'm at now:

Instead of just throwing money and parts at it, I had my mechanic (who I do trust) look at it.

He replaced the plug (to make sure), replaced the cable, replaced the coil, and replaced the injector. He cleared the codes on each part and read them when they showed back up. It's always Cylinder 3 that misfires.

Fortunately for me, he put the original parts back in since he doesn't think they're the problem and I just paid for his time. He thought it may be a problem with a broken valve spring or similar issue. Tomorrow night I'm pulling off the valve cover to see if any of the valves are loose or don't rebound properly.

[Sickblueb5]

Sounds like a compression issue now

[CommieHunter]

The mechanic checked the compression at 180 lb.

[CommieHunter]

I did replace the camshaft sensor, did not fix the issue.

I am thinking of replacing the plug wires anyway....

[CommieHunter]

So when I was in there messing with the cam position sensor, I did notice that the timing belt seems quite loose. I could probably slide it off the cam gear with my bare hands. Is it possible that something slipped a notch and my timing is off?

[O_o]

So when I was in there messing with the cam position sensor, I did notice that the timing belt seems quite loose. I could probably slide it off the cam gear with my bare hands. Is it possible that something slipped a notch and my timing is off?

Not likely, since the misfire is only on one cylinder. Was there oil in the plug well when you replaced it? What did the plug look like?