Power loss puzzle

Hi all,
I hope someone can help.
Ive had my jimny for 5 years now, its 10 years old, never a thing wrong with it besides normal replacement stuff, brakes tyres etc.
Mid JAnuary as i was coming off a motorway had a sudden loss of power, engine started shuddering, limped of the slip road at 20mph. Called the AA out, they checked it all, no leaks, nothing broke, no faults on computer. Was low on oil, so we topped that up. It started up fine and worked perfectly well for two weeks and then it did it again. AA man said at time it probably needs a good service (as i havent been able to afford it past two years) but all looked good otherwise. Took it straight to my garage who gave it full service. Sounded sweet! On way back from work next day it did it again! So straight back to garage...
Oh and it took half a tank of petrol over 25 miles.

now 2 weeks later i still havent got it back!

They have done every test and cannot find a fault, drove it and it wont go wrong for them.

So the only thing they can think of is that it may be the fuel pump but the only one they can get is £450, a bit expensive if its not that that is wrong

a, anybody got any ideas?

b, anybody selling a fuel pump cheap?

I want my JJ home

Pam x

p.s. I am an archaeologist and do take my J out to play with work

I would suggest the camshaft sensor at the back of the head if it is a G13BB engine. That was the intermittant fault with mine. Part only cost about $50 and it has been right ever since.

Thanks, will tell them to look at that

Mines a M13AA engine but from reading other posts i guess it will be the same.....

If it's the m13a when it lost power did the engine light come on and the rev counter jump about? If so it's the crankshaft sensor near the alternator

Has anyone examined the catalyst for being blocked?