Jimny auto engine roar - Sorted

My daughter has asked me to look at a fault on her 2006 auto Jimny. On medium to hard acceleration the engine peaks at 3000 rpm and makes a load roaring noise. Lighter acceleration does not have the roar but does lack power as the revs rise. The engine itself revs freely throughout the range when in neutral. My initial thoughts were for a gearbox fault but the noise is not from the gearbox area.
Can anyone help to throw any light on this fault please?

I have yet to take delivery of my auto one but certainly on the test drive it did nothing like that. Starting with the simplest first, when was the gearbox oil and filter last changed?

She's had the car three months and all has run fine. G/b oil looks clean although high. All road testing of the g/b has been good apart from this roar and 3k rpm lockout. As it is exactly 3k every time I assume it is an electronic problem, but is it g/b or engine?
Can anyone recommend a reasonably priced scan tool for the TCM?

I've had a mechanic look at this now. Really impressed when his feedback started with "I know nowt about Suzuki's, but...".
His scan tool showed no stored codes and just one pending of O2 sensor bank 2 which he reset. The car now has a bit more power and revs better, but could the lambda problem cause low power and a roaring noise? Am I better off taking it to a Suzuki dealer?

Check for blockage in the exhaust, or catalyst, and have a look at the air cleaner & inlet system for blockages too.

Thanks facade, you are thinking on the same lines as I am. My feelings are that it may be a blocked cat, which would explain the roaring noise involved. That will be my first check for tomorrow.
Has anyone managed to clear a cat, even temporarily, to confirm my suspicions? Perhaps a pressure washer?

Lots of pulling of hair over the last couple of days but it is now sorted. Although the exhaust is relatively new (still shiny!) the cat was blocked. Sprayed it through several times in both directions with the pressure washer then refitted. Back to full power and quiet again.
In trying to track down the problem I also found that the manifold cat was rattling so I removed all the bits to restore quiet. Test driving after cleaning both cats didn't produce a fault code. Now to wait for MOT time to see if it fails on emissions.

The problem was caused by the front cat disintegrating and blocking the rear cat. I smashed the front cat out, leaving an empty casing, and reverse flushed the rear cat with a pressure washer.
The car has run fine since then, and yesterday sailed through the MOT with 0.13 co against an allowed 0.20 on the emissions.

Should anyone else have a similar problem it would appear that the front cat is not necessary so you can save your money.

Good result
Thanks for sharing

wychall wrote: The problem was caused by the front cat disintegrating and blocking the rear cat. I smashed the front cat out, leaving an empty casing, and reverse flushed the rear cat with a pressure washer.
The car has run fine since then, and yesterday sailed through the MOT with 0.13 co against an allowed 0.20 on the emissions.

Should anyone else have a similar problem it would appear that the front cat is not necessary so you can save your money.

Good to know.
I have often wondered how much cat a motor needs to pas the MoT.
And is the rear cat not neutralised by flushing it with water. Shows how little I know about cats.:blush: