The car boost strong 99% of the time. Very occasionally when I get even on very light throttle from trafic lights, the car would judder violently and not accelerate.

THe second issue is that (and they may well be connected), under boost the car runs lean (like over 13+ afr) and judders, during this time whilst cruising in vac its leaner than usual around 16+afr (normally 14-15 afr).

The problem would then just dissappear when I drive it the next time which makes it hard to troubleshoot. What could be the issue here? Map sensor? TPS? Coils?

Anyone had similar issues?

 

Could be an injector, Map sensor..........but is not the coils. You need to do some datalogging to try and catch the issue on tape.

P.S. You may want to list your setup including details on your fuel system and ECM.

 

Setup is as follows:

AEM FPR
RC 750cc injectors
Walbro 255
AEM EMS
GM 3 bar mapsensor (I think its GM not 100% sure but its from Full Race)
Golden Eagle Vac mani

Custom tubular mani
GT35R
3" DP & exhaust
Tial 44mm
Tial bov
FR fmic

If I change out the 3bar map with another 3bar map of another brand, would the tune be out and need a retune or would it be ok?

 

or tps.a week or so ago someone posted this same problem.im waiting on a another tps and ill let you know how it goes