Hi guys, I'm having some major issues with my engine. It has 135,000 miles on it, and its having a major misfire on all cylinders. Its also giving me a p1606 engine torque code. Happened to me today after driving 3-4 miles and I immediately pulled over to see what was going on. VAGCOM gives these codes: p1606, random misfire, cylinders 5+6 misfiring. Pulled the fuel pump fuse to eliminate the fuel system being the fault, still misfires on cranking and makes a loud tapping sound. Pulled part of the timing cover and the belt looks like its in pretty good shape, although I have no idea how many miles are on it. I'm convinced this car is cursed, because I was finally gonna have it in good running shape until this happened.

Recent work:
SAI Pump
Rear O2s and custom catback

Less recently, I had the Camshaft Position Sensors changed because VAGCOM threw a code for them, and the car was flashed over a year ago by Speedtuning. Has newish Bosch wires, a new air and fuel filter.

Any advice or guidance would help very much, I'm desperately hoping its not the Cam Chain Tensioners that failed, because at this point I'd write the car off. Can't afford to fix that.

 

Bumping, I ran VCDS' misfire count. Cylinders 1+2 seem to now be main offenders, in 30 seconds they each misfired 200 times, cylinder 3 just once. Nothing on bank 2, which I found odd since 5+6 originally had their own misfiring codes on my first scan. Hoping its the coilpack or ignition control module, could anyone describe/confirm the symptoms of each?

 

Another update, changed the coilpack and it idled normally for a minute or two until I started giving it gas and it began misfiring again. So not the coilpack. And I discovered I don't have an ICM. If it were a timing issue such as the cam tensioner failing wouldn't that cause misfiring across the whole bank? Only other thing I can think of is a massive vacuum leak, but I've glanced around the lines and didn't see anything out of the ordinary. The thing thats killing me is that VCDS isn't giving me any helpful codes, just telling me I have a misfire. I could really use some advice guys I'm in a bit over my head right now.

 

Just my 2 cents, but if your cat is blocked, it can make your car misfire and put it into limp mode and pull a bunch of different codes....I've seen all kinds of codes, but since you just had the catback modified.....and it wasn't doing it before....also, remember, the ECM learns and adjusts to your car as you drive it over the years....which means, if you change something drastically after many miles, it can throw codes and make your car run like......

Just glancing at the hoses isn't going to tell you there's a vaccum leak, there's a bunch of hoses and I've replaced mine twice...and if timing is off, it can fail just one bank or others...have you checked your MAF? Clear the codes, unplug your MAF sensor, run the car and see if it throws codes, runs better or the same....check your spark plugs and plug wires.....it could also just be the chain tensioners are worn....they are just plastic guides, doesn't necessarily mean your chains are bad....

But if it started happening after your catback...I'd start there...

Also, the can throw the cam positioning sensor and be something else like the guides...how long ago was it swapped? Were you having some related issues before/after the sensor was swapped?

 

Car was fine for like 150 miles after the catback before it started acting up. O2 sensors passed readiness before the car acted up, so I'm assuming they were getting proper exhaust flow, not to mention I do get plenty of exhaust flow with the new catback, so if the cat were blocked I'm assuming that Id know. I might not though, you tell me.

Cam sensors were about 800 miles or so ago, I had a code for them and swapped em out. No running issues, it was precautionary because I do have a lot of miles on these cam chain tensioners.

I figured the hoses were fine because they look fairly new, but you are right I didn't thoroughly check them, its on my to do list.

For what its worth, last spring I had a similar problem with misfires, turned to be a clogged fuel filter. I'm not entirely sure how to diagnose the fuel system, so I can't rule that out either.