So I have a mk2 with an abf conversion which has been faultless until all this rain.
Started off with rough running when cold so changed coolant temp sensor. Drove through water, car runs rough so ordered a crank sensor. Started misfiring at medium revs and rev counter went crazy, pulled relay 30 whilst driving and pushed back in car run fine so I replaced that. Braved the rain yesterday and changed crank sensor, not sure how tge car even ran. Insulation was crumbling and bare wires were touching in at least 6 places. Go to start car, eventually starts but misfiring because the coil is arcing through the plastic casing so swapped for a spare. All fixed I thought. Drives spot on now until I start it from cold and I'm back to where it all started. Starts fine high idle as it should but as it warms up it idles rough and cannot be revved. Once slightly warm it's spot on. The coolant temp sensor is genuine Bosch and tge plug has just under 5v. If I pull the plug whilst running there is no change. If I try start it with it pulled it won't start. I was convinced it would be an earth issue due to weather but all seems ok if I do a continuity test with my meter. No idea what to do next but it does seem to be all down to coolant temp sensor. Also I find it weird that everything goes wrong at the same time. Any ideas what to check next?
