Dreaded Cylinder 4 Misfire

[boogz]

Hello...

So I've just received a phone call from my mechanic and it was not what I wanted to hear at this time of the year...

Symptoms - rough idle, loss of power, engine light on
Diagnosis - ran a diagnostic and got the dreaded P0304 (misfire in cylinder 4) and P0030 (O2 sensor error/failure) & compression test
Treatment - change spark plug & change ignition coil
Result - Slight improvement, but still rough idle, engine light came back on after clearing
Other theories - Stuck valve, worn cam lobe, stuffed piston (possibly - worst case)

Mechanic's advice - either open it up and see what the problem is or a replacement engine

Anyone got a spare 1.4 tsi motor? or know if anyone is selling on

[Mattlock]

I had a cylinder 1 misfire earlier this year on my 1.4TSI and it was crud stuck on the valves stopping them closing properly. My mechanic took off the inlet manifold and cleared the crud off with picks. The end result was no more misfire/CEL and the idea sounded gruffer and I had more power and quicker rev changes.

It cost me about $650 to get it done and was well worth it.

[Umai Naa!!]

Yep, run an intake cleaner through it, and see if it improves.

[milldinho]

Hope this helps

Copy and paste from rosstech site.


16688/P0304/000772 - Cylinder 4 Misfire Detected

Possible Causes
Ignition system
Fuel injectors
Fuel pressure
Running out of fuel
EVAP canister purge valve
Evaporative emission system
Low compression

Base engine problems
Controle Module damaged

Special Notes
This feature search for engine misfire in a specific cylinder. Most of the time the cause for a misfire is a lack of combustion in a cylinder due to absence of spark, poor fuel metering, or poor compression.

[The One]

Want's to pull the motor apart, yet hasn't posted compression readings? IS a cylinder down?

[vdubmotorworx]

Take it that we are talking about a CAVD twin charge...did he rule out injector? Get compression readings from your mechanic. Piston damage is ususally down to about 70 psi while the other cylinders read around 180-200.

[vdubmotorworx]

If it is piston damage suspected take it a dealer as most are still being repaired either full cost or part cost by vw as long as good service history....yes even out of warranty to are supporting this issue

[Snail Style]

He didn't mention the compression test results or if the misfire followed the movement of the coil/plug. :S

[boogz]

Take it that we are talking about a CAVD twin charge...did he rule out injector? Get compression readings from your mechanic. Piston damage is ususally down to about 70 psi while the other cylinders read around 180-200.

He didn't give me the exact readings, but said that the tool didn't even register any compression/pressure.

[boogz]

I'll let you guys know how we go after the 12th Jan. Since my original post, he was meant to run an injector test and if that didn't bring up anything, take the head off and have a look. But he's on his break so won't know anything till post 12th Jan. Keep you guys posted. But thank you for the feedback.

I've been trawling online for replacement engines (worst case scenario) but someone did mention taking it to VW. I've reached out to them also to see what they'll do.