Phillip.weston, your advice please.

I picked up a '90 NZ new Magna (Sigma) wagon not long ago (was too cheap not to lol) and has lately developed a couple minor issues.

It's a 2.6 & manual done approx' 300k

Under load it has a jerky hesitation, but only when accelerating, nothing when driving at constant speed. The other thing is it 'runs on' when you turn it off.

It's a thirsty pig, i've read the 2.6s are but this thing is unreal lol.

Would the 3 things (hesitation, run on & fuel consumption) be related to timing!

Otherwise it's a great wee ( well not wee really, the damn thing's huge haha) car.

Advice appreciated.

Check the oxygen sensors,they can play up causing jerking,rough running,high fuel consumption.

is it carb or MPI! Also don't confuse the Magna with the Sigma, they are technically two different platforms and share little other than some external body panels.

it gets even more confusing due to the local names for the cars. The Sigma in NZ as we know it is actually a Galant with the RWD models being the 3rd and 4th generations while the FWD Sigma being the 5th generation of the Galant.

The first Magna was its own platform derived from the 5th gen Galant platform - the chassis was widened approx 3" down the middle for more interior room but also to accommodate the longer 4G54 engine which up until then had only ever been mounted longitudinally. The front MacPherson strut suspension carried over but the rear suspension differed, especially on the wagon models which was basically a triangulated four link setup where the sedans and the 5th gen Galant had a three link torsional U-beam with a panhard rod.

Externally only the front guards and the doors were the same (and rear quarters on sedans) - everything else like bumpers, windscreens, bonnets, roof, bootlid etc were wider. The interior also had a wider and different design dashboard, center console and seats. The wagon is unique only to the Magna and was never offered on the Galant platform it was based on.

The it gets a bit more confusing with the 2nd generation Magna (rounder model introduced in the early 90s) which was based on the 1st generation Diamante platform - this very platform was actually badged as the 'Sigma' in Japan for the lesser spec framed windowed models while the upper spec with frame-less windows were badged the Diamante. In Europe the whole Diamante range was badged as 'Sigma'.

also I would check for carb related issues - could be a partially blocked jet or leaking accelerator pump.

Check idle speed is at around 750-800rpms and check ignition timing is set to about 5-8deg BTDC depending on what octane fuel it's running on. Check condition of coil, distributor rotor/cap and spark plugs and check spark plugs are the correct heat range, they should be BPR7ES or something similar.

Well for what its worth , You should buy and fit the correct NGK spark plugs, I had a 1992 wagon years ago, it was a good car, did 100,000km on top of the already 120,000 and was good, no problems,cam chain bit rattly at idle, anyway if put some long life champion plugs in it (don't no why i bothered), from that day onwards it had a slight miss(if you could call it that), of coarse i took it into a couple of places to get it fixed, they couldn't fix it, after a while later i called into a proper mitsi place and the tech looked at it and straight away said they had the same problem with one of their customers car and it turned out to be the plugs. So back to the NGK and all fixed. Don't know if this is your problem or not. Good luck.

yeah for some reason Mitsubishis don't like Champion plugs - I've always run the standard copper NGK plugs and have had no issues.