Strange missfire

[Flames83]

Hi all
Iv got a strange missfire between 1500 and 2000 rpm dose not do it all the time if I hold revs at 1500 rpm for 30 seconds it get lumpy ? Plugs done 4000 miles same as coil packs (aftermarket ones ) it’s had new tdc and mass air flow sensor with lamber last year not warning lights up . Dose not miss a beat after 2000rpm . Any suggestions would be appreciated

thanks

 

[suj]

They don't have mass air flow sensors, they have MAP sensor (manifold absolute pressure), so did you change that?

Does your car have an aftermarket exhaust? If so it's common to have a "flat spot" that feels like a misfire at 1500-2500 (varies in that range per car), if you have this you can get the car mapped that flattens down this misfire to a point that you cannot feel it any more.

 

[Flames83]

Hi
Yeah that’s what i meant, no all standard . It’s more then the flat spot had the car 4 year and this is new.it’s Really annoying me