Golf is misfiring amongst other multiple electrical problems

[Dan_93]

Hi all, so I've been having an extremely difficult time trying to diagnose and repair this and I'd be really appreciative if anybody could point me in the right direction.

The car is relatively low mileage for its age of 22 years old, its at about 78k. It's a 1.6 petrol, 2000.

The last 6 months I've been having numerous electrical gremlins. In an attempt at simplification, I'm going to try to split this into two parts.

Firstly, I have a constant misfire. It tends to fade once the engine has warmed up and then will be fine if you just want to drive about town, but problems return with a vengeance if you attempt to drive long distances on main roads at 70. After about 10-15 miles, I get engine warning lights, and then what happens is this: the 3 warning beeps sound, the center screen shows "STOP, oil pressure" (nothing I can see wrong with oil level so I'm assuming its an electrical fault), the rev counter drops to zero, and the power steering turns off. At that point the car will keep driving forwards (presumably so you can find a safe space to stop?) but when you slow down, it won't speed up again, it will slow and then die. After 10 seconds or so, you can then turn it on again and drive normally, all problems seemingly gone. If you use a fault code reader, it's always code P0322 - "ignition engine speed input circuit no signal." This is the first, and most consistent part of the problem I'm having. my intuition would be a faulty ignition coil, sensor, or wire, but in light of the other symptoms, I'm not so sure.

The second part of the problem I'm having is multiple electrical gremlins. My center screen will sometimes randomly flick between speed/mileage/fuel economy etc settings. My radio was occasionally turning off, though that doesn't seem to happen anymore. My heated wing mirrors recently failed, and my map light stopped working properly. My wheel speed sensor failed, as did my knock sensor in quick succession (I replaced both). In addition to this, I've had about 4-5 other random fault codes appear, such as lambda sensor, but now it seems to be consistent with only coming up with P0322. In light of all these things, I'm loathe to just keep buying new parts to replace failed ones in order to see what happens, as I just feel like it'll make other parts fail instead?

Someone please help, its driving me nuts!