Misfire On Acceleration

[Guest Pedro]

Hi everyone, My mystery hesitation/misfire has returned despite renewing numerous ignition parts. This only happens on acceleration when overtaking etc if you back off the throttle and cruise at 40-50 its ok.

 

This happened when returning from the local supermarket where I added approx 15ltrs of unleaded, it was ok on the way there. Looking back I think the last time this happened was again after I had used supermarket fuel. This is ok in my tin top but perhaps not in my 1800 Pinto with modded cyl head?

 

Has anyone else come across this issue? I have ordered new fuel filter and pump , think I might drain the tank and use Shell V Power!

 

Thanks again

[Guest peter2b2002]

tesco fuel did that to mine a few years ago

peter2b

[Guest Sevenheaven]

Might want to check the valve clearance on a pinto, this happened to a friends 2B but only when up on the power the same as you.

 

Alan.

[keith kelly]

Fuel starvation, going too lean under load maybe?

[HAWKNORTH]

Many years ago I had a mini clubman that ran perfectly unless I put fuel in it from a local Fina petrol station. Any other petrol brand and it was okay. I'm not saying this is your problem, but it reminded me of that old mini.

[Guest Pedro]

Thanks for the info, just replace the head gasket and did the valve clearances with that ( had the misfire previous and after this work). I recently fitted a new Weber carb and just guessed at the slow running mixture, turned the screw out until the engine was lumpy on tickover then in a turn until it smoothed out. Engine ticks over and revs great when standing its just under load, got a new fuel filter and pump to replace Monday and am going to syphon out the fuel in the tank and replace with some good stuff

 

Thanks.