I want to add a relay to the fuel pump circuit to try to remedy the problems I'm experiencing with intermittent electrical problems. Adding a relay and a fuse won't be a problem, but I'm stumped as to what might be causing the symptoms.

Car stalls and behaves erratically and quite irregularly. I think it is due to power cuts to fuel pump power feed. I have changed the fuel pump less than a year ago. I have also checked and cleaned the earths. I have tried several different fuel pump and ECU relays (in the bulkhead). When the problem is "on" the fuel pump feed is pulsating and the fuel pump relay clicks in the same frequency.

I'm thinking also that the symptoms might coincide with weather conditions - when it's warm and dry everything works but when damp and cold the problems are worse.

First I suspected that the coil(s) were the culprit but changing them didn't have any effect. I might replace the plug wires just to be on the safe side.

So my question is what other places to check and what I need to double-check Any suggestions are welcome as the problem is very frustrating ad renders the car a useless piece of junk