My daughter has a 1600 Ford Zetec engined Fiesta with lowered body, sideskirts, air spoilers etc. Looks the business but it's like driving a plank of wood with an engine bolted to it! (She loves it though).
Recently it has developed a low speed misfire which causes stalling and sometimes stops it starting. After one breakdown we got it going again (not sure what we did but it started) and i followed her home. I noticed that using the indicators and brake lights caused a christmas tree effect on the rear lights. I knew that means an earth problem. (The car has non-standard triple circle light clusters fitted in place of the original).
Found the earth in the boot and it was loose. Tightened it up - and no more stalling! The trouble is it's a self tapping screw into the body so it loosens itself after a while and the problem comes back.
Why does an earth connection in the boot affect the engine? The engine earth strap is fitted and tight.
Any ideas?