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Message: <blockquote data-quote="hamsap" data-source="post: 801830" data-attributes="member: 1832">Hi guys,Have gotten into some problems with the car jerking when WOT.Engine - CD5A 4G93TStock formECU: 5663Manual (if that helps..)When WOT, I noticed that the boost comes in much earlier but the car is not pulling/ moving. We've gotten the spark plugs changed and gapped correctly (factory recommendation of 0.7mm - 0.8mm), gotten a wideband dynojet A/F meter strapped on and the A/F ratio seems fine (WOT reads around 11 - 12.5)The next thing we did was rewire the fuel pump to get its electric supply directly, hence making it work more efficiently. Worked ok for a day, and the next day the same problem persist: Gradual acceleration on the accelerator= fine. WOT=bogs down the car, not accelerating as it used to be but I noticed boost comes in much earlier.Ok, we have come to a few possibilities on why is this happening:1.)Fouled spark plugsCouldn't be cause the plugs are only 2 weeks old. Rating is 7, used 6 previously and it lasted me for only 2 weeks before it started misfiring http://www.4gtuners.com/forums/style_emoticons/default/smile.gifProperly[/URL] gapped at 0.8mm proportionately on all four plugs2.)Faulty internal wastegate/ boost actuatorBoost reading stayed constant at 0.6 - 0.7 all the time. Now if it is jammed, then I would be reading a higher boost. If the wastegate actually opens up to earlier, wouldn't I see a lower boost reading or a boost reading something like 0.6 then 0.4 and then 0.6 again?What I'm trying to say here is that if the actuator opens up the wastegate much earlier then it's suppose to be, I shouldn't be seeing a constant 0.6 bar of boost right?3.) Faulty fuel pumpThis might be the problem, I dunno. Just need to see if any one of you have faced such problems before. Now if it's a faulty fuel pump (or for that matter, injectors, FPR, fuel rail) which is not delivering enough fuel to the engine, I would be seeing a A/F ratio reading of 11 - 12.5 right?) Or is this because the ECU is somehow smart enough to detect there isn't enough supply of fuel and hence retard the timing?My car is the second car that is facing such problems. Mech is still cracking up his head trying to figure out what's wrong, so hopefully there is someone who had faced such similar problems would be able to shed some lightP/S; Fuel filter has been changed last 3-4 weeks agoThanks!</blockquote>

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