[Sorbus]

Ever since I had the clutch replaced recently I have noticed two issues...

1) Speedo sometimes not working.
2) Engine feels like it is misfiring (lagging and pulling), especially at higher speeds.

I have replaced the spark plugs, but the issue persists.

What is confusing me is that while the speedo isn't working, the engine doesn't seem to pull/lag. I don't know whether that means the engine is permanently lagging so that you can't feel it, or whether it's working fine, but only when the speedo isn't.

Does anyone have an idea what could be causing this? Some sort of link between the two issues.

Usually I do all the work on the car myself, but the clutch was too daunting and I needed it fixed quickly so I went to a garage, who are now saying the engine was misfiring before they did any work. That is definitely not true, and basically I want to have an argument with them, but without knowing the cause of the issue (if it is related to the work they did after all) it's an argument I'm bound to lose.

I've recently changed the rear axle, all the brakes, a wheel bearing, had them do the clutch, taxed and insured it. I've spent more than the car is worth on paper frankly, and I really want to keep it going for at least another year.

Any insight is greatly appreciated.

 

[reliable406]

Earth wire on gearbox not tight there is 1 for the battery 1 for main loom speed sensor not plugged in correctly in gearbox or wiring touching driveshaft anything is possible but you dont say what age so you may not even have a speed sensor !!

crank sensor loose bad connection damaged during clutch job another possibility

 

[Sorbus]

Thanks very much really appreciate it, I'll start checking that out. Having done a quick bit of reading it sounds like it could be the crankshaft sensor. Is there any way this could also be connected with the speedometer intermittently failing?

It's 2000 model, 2.0 petrol.