Dear fellow Alfa lovers,
A year ago I bought a 156 1.8TS Facelift, ran great but needed some minor work, which included the cambelt and variator.
I´ve completed all the maintenance, and the car runs great! I´m very happy with it
Buuut, (yes here it comes) a month or two before i changed the cambelt and variator, the car would suddenly run incredibly rough on cold mornings, throwing P0300 codes, initially only on cylinder 3 (P0303) but will gradually throw misfire codes for the rest of the cylinders.
When the engine gets warmed up, it will run on 4 cylinders, but the engine still shakes intermittently, and sometimes run on 3 cylinders (p-p-putting).
It idles at 800 rpm when warmed up and 1000-1100 when cold.
I suspected the timing was off, since the cambelt was definitely in need of replacement, and furthermore was fitted by a non Alfa garage, the cambelt change was probably going to be the solution.
Well... So I thought, upon changing the cambelt the timing was definitely off, and the variator knackered, I changed the whole assembly, noting the timing was right.
Initially after the replacement it did drive better, but it still ran rough on cold mornings, the problem was still there..
A couple of weeks later I got a couple of days of work, and went to check the timing again, maybe it was off again? Timing was perfect... The cam locks went on perfectly at TDC.
Hmm, so I went to measure the compression... The compression on all four cylinders are within specificiation, the plugs are new, and so are the coil packs and leads (They we´re cracked, but the resistance was actually OK)
Maybe it´s an air leak, borrowed a smoke machine from a garage in town, and fitted it onto the intake manifold, and no smoke to be found...
Well maybe the camshafts were worn then? It was a thought, but they are A-OK, I got them checked by a Alfa specialist here in town.
Lambda readings are within range, the fuel trims are good, I dont know where and what to look for anymore
Maybe the fuel evapouration system is at fault? And i´ve thought of hooking up an emissions tester, to see the readings.
At this point it cannot be anything else than an air leak, somewhere...
The engine runs beautifully throughtout the whole rev range, and is as fast as always.
All suggestions are welcome!!