Car is a '93 Mk1 VW Cabriolet, 1.8lt injected.
The car has had trouble starting - feels like only some of the cylinders are firing. If I rev the engine a little the problem goes away after a few seconds and the engine runs as normal. This does not happen whilst driving, only at start up. Does not seem to make a difference if the engine is warm or cold. Once on the road the car feels fine and is normal to drive.
Thinking it was the plugs, I replaced them, but after only about a week the problem returned.
I also noticed the fuel economy isn't as good as it used to be.
What could be causing these issues? Timing? Distributor?