Hi all, have had a look through search but not managed to find exactly what I am after.
For the past year (since owning the vehicle) it has had a slight tapping noise on cold start up, goes away after a few seconds. Thought it was either the lifters or manifold gasket, bought enough oil to do 3 quick changes to eliminate the lifters, only done the first change and 300 miles so far! Took the heat shield off the manifold and manifold looks fine, no sooting obvious. Just tried tweaking the nuts, and 3 of them were loose, two on cylinder 4, one on cylinder 1. Put it all back together and drove for a couple of hundred miles, no change in the tapping on cold start.
Now for the last two weeks, it has misfired on cold start, only for about 10secs, then ran fine. This has got quickly worse over the last 5 cold starts. Once the car with a spanner light came on for a minute, and then cleared as I picked up to about 40mph. Now it has the misfire continuously. Not allowed it to warm up fully, but it didn't go after 5 mins so stopped before causing damage. EML came on with:
P0303 - Cylinder 3 Misfire
P1781 - Engine Torque Signal Circuit (pending)
Any ideas where to start? Would like to investigate in the most logical order and with least amount spent (but happy to replace faulty parts with OE ones if necessary).
Have just got plugs as not sure when they were last done, any way of checking the coil pack is okay?
Thanks in advance for your help!