Just a wee update. Hadn't got around to getting the TJ looked at...lack of power was still prominent but I was getting up and down to work at 100kph so decided to leave it. I'm off on holiday on Saturday so planned to drop it into the mechanic whilst away.
BUT..yesterday I was driving up Sheikh Zayed Road....car was struggling to get the usual 100kph and eventually wouldn't go above 80. After 15 mind the checks gauges light came on and the temperature shot up. I managed to get pulled over, and car recovered to mechanic.
He called there to tell me it's the muffler box that need replaced. Again, I've no idea about this stiff so does it sound plausible that a faulty muffler would have been causing these problems?
EDIT: been quoted around 150 quid for this repair. That's on top of the 380 he charged me last week to replace O2 sensors...