Hi,

Can anyone help?

Driving in 1st, 2ndand 3rd seems fine it'll get to the limit. But when I shift into 4th and 5th the power completly goes! expecially if it's under 3000 revs. I can get 90mph out of it going down hill on the moterway with my foot to the floor.

I have a engine light on which says PO0037 Heater Control Circuit Low.

Reading on here it sounds like it maybe a blocked Cat which I'm thinkings of gutting and decatting.

Would you think this would solve this problem?

Thanks

 

Possibly. You've never had any CELs for misfires?
That's usually what makes them go bad. Drop your cat & inspect it. You don't want to gut a good $1400 cat.