2.0 JTS misfire help required!
A brief history of my problems:
After owning what must be 30+ Alfas and never having any major or unrepairable problems, I recently bought a GT 2.0 JTS with a snapped cambelt.
I changed the cambelt and water pump initially but when it started it was only running on 3 cylinders.
Due to a lack of time, I sent it to the garage I always use. They found that there was damage to one piston, injector and valves. I had new valves fitted, new piston, new injector, head skimmed and replaced a coil with a second hand one.
Got the car back and it drove fine, but with one issue. It took quite a few turns before the car would start. After doing some research, it all pointed to cam position sensor. Back to the garage, new sensor and starting issue resolved, but now there was a new problem. When the car gets to 90 degrees, at exactly 3000rpm there is a 'misfire'. The misfire sounds very metallic but im fairly sure it is a misfire. Once you got to around 3500rpm, it cleared.
I have spent 3 days changing and messing with items on the car with no fix, but I seem to be getting closer. So far I have changed all the coils, plugs again, oil, cleaned all the electrical connectors I can think of, cleaned the earths drove the car with things disconnected, and the problem is still there. There is a slight difference now though. It will do the misfire 2 or 3 times when up to temp and then nothing and will be fine. Switch the ignition off and on again and it will do it again, just once or twice.
After spending all day on it today, I have discovered that with the temp sensor disconnected, the car is fine and never misfires! Thought I had solved the problem, so I fitted a second hand temp sensor. Still not fixed! Long shot, but maybe both sensors are dodgy? So off I went and bought a brand new sensor. Still not fixed! I am now totally confused! Any help would be greatly appreciated.It has got so desperate that I have bought a spare 156 JTS to take parts off! Anybody know of the relationship between the temp sensor and maybe the injectors or coils?
Apologies for the long thread but im at my witts end now!