Outer Limits 4x4 Board

hey guys on monday i filled up my tank at a different servo thatn usual put 98 octane unleaded in my mav. anyway ran fine for the first 150 ks now, when i start the car it is missing badly, once it gets to operating temp at idle it runs smooth but for about the first, 10 to 15 minutes you drive it it coughs splutters misses and backfires. i would have thought if it was fuel that it would have stuffed up almost straight away. Anyway i have checked plugs and leads, i have elec ignition so it cant be points. Any ideas or should i just drop the fuel replcae the filter and see what happens.

could be one of a few things, possibly auto choke problem, a crook lead or plug, maybe even a crook coil. id start with the cheaper things like plugs and leads, then filters, check the timing too

Are you losing any coolant , or is the overflow gaining any coolant. This could be signs of head problems , very common on these.

nah its not the head had that tested about a month ago. and no coolant loss or pressurising of the cooling system

Fuel filter...maybe you got some dirty fuel and the fuel flow is being impeded.

sounds like the auto choke to me

ok so i dumped the fuel and changed the filter ive done nearly 60 k's since and still have the same symptoms. So lets assume its the auto choke (even though i had my carby rebuilt less than a year ago) what do i do to fix it, i would normally take it back to the shop that rebuilt it but ive moved and they are like 100 k's away then.