Talk Morgan Forums Thread Like Summary - 2010 4/4 engine power loss

I've generally got two left hands, so any advice will be helpful!

My Sigma engined 2010 4/4 has been running fine until a few month ago. Now, after a specific set of circumstances it badly stutters.

After warming up, any revving above 4000rpm causes the engine to stutter, very similar to fuel starvation I had on an old Sunbeam Stiletto I used to own (that was a rusty fuel tank clogging up the fuel filter - an easy fix!). If I depress the accelerator in any gear there is a severe feeling of starvation, stuttering and shuddering. Keeping below 4000rpm seems to be fine.

This happens if I push the car above 4000rpm while driving (in any gear) or pull over and rev the car while in neutral, then drive off.

If I stop and rest for a few minutes the issue goes away, but then comes back.

For the first 60 minutes of driving I do not notice the problem.

I live in NSW, and have the car serviced at a great, small local garage. But, they are not Morgan experts. They plugged in an OBD2 port but couldn't identify the problem. They changed HT leads and plugs, cleaned the MAF sensor and cleaned the connector on the accelerator pedal. But, all to no avail. Any thoughts on where next to investigate will be very helpful!

There was a similar post on here for an arp4 where the cat had broken blocking the exhaust gas flow. Or it could be fuel starvation

Thanks for the great comments - I'll work through it one-by-one and update the post when (eventually) I solve it to help any others with a similar problem.