Hi All,

Am now at wits end, cylinder 5 is misfiring when cold and when reved briefly. Cylinder 2 sometimes misfires with 5 (10% of the time), Cylinder 6 rarely but I have seen it while monitoring. Only raises an error code

Have done

1) replaced coils
2) Replaced ignition cables
3) Replaced the spark plugs
4) Replaced fuel rail and injectors with known good ones
5) replaced the cylinder head cover gasket (small amount of oil in sparkplug)
6) Did compression test: - Cylinders 1-3 about 195psi, cylinders 4-6 185psi - same across all cylinders
7) Did leak down test - small amount of leakage when engine was cold (into oil) but fine once warmed
8) Replaced MAF with secondhand Audi one
9) replaced air filter (very long shot - had one for my next service in March so decided why not)
10) replaced ECU
11) Put in Cat cleaner
12) Put in Injector cleaner
13) Replaced vacuum solenoids with second had ones
14) replaced old vacuum lines
15) Disconnected left Cat (in case of blockage) - was very noisy - did not fully disconnect though, just loosened.
16) changed oil/oil filter (Oil was fine no traces of coolant in it)
17) tested wires to injector 5
18) replaced fuel filter

At this point only things left are:
EGR valve - could a bust one cause mis-fire on only 1 cylinder?
Coolant temp sensor
Dud Camshaft adjustor/sensor

Or the cat is the problem - waiting for pressure guage to check.

Any other ideas?

Hopefully from the above I can rule out head gasket/Valves.

Any help much appreciated,

W

 

Try swapping the coil with one you know is working properly maybe you got a bad/new one??