Check engine light - weird readings

Hi,

Getting car ready for MOT after a load of work. MGTF has been off the road for a year.

I have had a check engine light appear a couple of times whilst idling. Earased but coming back.


Code is P0170, nothing else.

Freeze frame data is weird.


Load% 0.0
ETC(0c) 136
SHRT FT1 ( -100 )
LONGFT1 ( -100 )
MAP(Kpa) 0
RPM 0
VSS 0

My understanding is that the freeze frame data is when the error was logged. Reading this, the car was warmed up but the the engine was off (no revs) and was hugely rich with the fuel trim trying to compensate.

Anybody make sense of this?

I used a Autel Maxiscan MS309. Cheap one the previous owner left in the car for me.

Fairly sure the airbox was back on when this code popped up.
One gallon of at least year old petrol in tank. Will be running down and putting fresh in for MOT (if there is any left after the current panic buying).
Previous owner replaced cat and one o2 sensor (doesn't say which one) three years ago. When i changed spark plugs - normal colour.

Car runs fine, idle steady, temps all good.

Cheers,

Iain.

I always chuck a load of super unleaded in after the car has been parked up for a while, normally Tesco 99ron as it's the highest rating of the suppers and having the nearest branch a few hundred yards away helps.

Actually got some petrol in a can and drove the car down the road a bit on a Sunday evening when the road was quite.

Just a pre MOT test run.

No engine warning light, time will tell but seems happier some decent petrol.

Noticed car drifted to the left slightly (probably road camber) but pulled to the left quite hard on braking. Going to have to check as it will fail on brake imbalance. Going to be sticking piston, dirt in caliper where pad slides on body or I may have got underseal wax on disc.

Going to be fun, the calipers are ap 4 pot = stuck pins.