Jimny lacking power no go top end

[whetren]

Okay so my misses brought a jimny xreg and it just doesn't seem to want to go it goes 70 flat out on a flat road and then when u get to a hill it drops to nearly 40 mph after changing into 4th gear? it's (from history) Been well looked after serviced up to date now i know it's had a new exhaust and the engine management light has come on I reakon it's a lamda sensor cas it's just had the exhaust done not long before she brought it I have cheked for slack in the throttle cable and there was a bit so I ajdusted it and it mad a small difference but not a lot now I'm thinking (oh I thought I better ad it struggles to start in morning foot to the floor little rev and she's fine but still anoying) anyway yer plug it in find out whats bringing the light on and fix it then new set of plugs and probably a service and see what it does then what do we reakon anyone had this problem ? Thanks

[Edweird]

It's probably something relatively minor. I'd go through all the usual service things, like oil, filters, plugs etc. and then try and get a fault check on it. The ECU might be able to tell you if there's a problem with a sensor. It could also be something daft like it's in limp mode.

[Anton]

Sounds to me like it's ECU is in limp-home mode. If you can plug it in and get a fault code, I'm sure one of us can point you in the right direction.

[Ju]

Limp home mode would just limit the revs. I would get someone to plug in a diagnostics tool before you do anything. They are not the greatest when it comes to hills in the first place, but yours does seem like it is worse than usual. What size tyres have you got?

[whetren]

It's just on standard tyres 205 70 15 i think ? Yer I can get it plugged in for free so I will do when I have a minute but yer just annoying I reckon it is just something simple well I hope so anyway thanks for your help

[trotter]

Blocked cat?

[Rhinoman]

I would put a new lambda sensor in and then if its still bad start checking the readings from the sensors. Use the fuel trims and lambda readings to check for a rich or lean mixture under load. Have a good check around for vacuum or exhaust leaks and check the ignition timing as well.

[whetren]

Okay I'll have a good check I think it is the cat tho as it has got a lot worse today and when it between 3 to 4 thousand revs It sounds like the exhaust is blowing so I'm gona undo it from the manifold and take it down the road and see what it's like