Misfire Under load/heavy acceleration

[v6nutz_2012]

Hey guys, been having this problem in my VP V6 wagon for a while. Coils, DFI module, Injectors, Fuel Pump, Leads and Plugs have been changed. Thought it was a vac leak at an improperly seated injector but with that problem fixed is continuing to do the same thing.
Anyone able to shed some light on a possible cause?

 

[hi_ryder]

whens the last time you did the inlet manifold gaskets.... sometimes water sneaks by and can cause a flutter under acceleration.

 

[v6nutz_2012]

whens the last time you did the inlet manifold gaskets.... sometimes water sneaks by and can cause a flutter under acceleration.

Honestly, haven't done them since i've had the car, and i've had the car for a good 5 or 6 years :/
Is there any way to know if this may be the problem without taking the manifold itself off? Or is it just take it off and hope it's the problem?

 

[wod300]

Have you checked for codes?
Just some thoughts (though mine is a vx):
Fuel filter?
Cleaned the maf/map?
Cleaned the throttle body/tps?
Air filter?
Fuel regulator?
Correct plug gap?


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[v6nutz_2012]

wod300, No codes thrown out at all.
TB was changed for a clean (spare) one I had, new TPS but reused IAC valve (was done way before this problem occured)
VN-VR has MAP, checked connections were tight/clean
Air filter clean
Have yet to check reg. How do I check that exactly?
Going to be taking plugs out to check, they are about 6 months old though and car only gets driven twice/3 times a week
Also will be changing my o2 sensor (due to it using a little more fuel than usual and the fact it hasn't been done since i've had the car)

 

[Brett_jjj]

Were brand new coils fitted or second hand ones?

 

[wod300]

wod300, No codes thrown out at all.
TB was changed for a clean (spare) one I had, new TPS but reused IAC valve (was done way before this problem occured)
VN-VR has MAP, checked connections were tight/clean
Air filter clean
Have yet to check reg. How do I check that exactly?
Going to be taking plugs out to check, they are about 6 months old though and car only gets driven twice/3 times a week
Also will be changing my o2 sensor (due to it using a little more fuel than usual and the fact it hasn't been done since i've had the car)

I doubt it will be the regulator, but if it was stuffed, it would cause problems. I'm not sure about checking the regulator in the VP, but in my car I just remove the vac line from the regulator with the car running for about 90seconds, if you get a little fuel coming out, then its gone.

I wouldn't be surprised if it is the plugs. I had the same problem so I changed the plugs/leads and it fixed it. Turned out that the mechanic had put the wrong plugs in (had n/a plugs in rathert than the l67 plugs, and they were gapped to 2millimetres!!!)

Anyway good luck and let us know how you get on.

 

[v6nutz_2012]

Were brand new coils fitted or second hand ones?

They were second hand ones off a VS, that car ran fine with them though so would be unlikely to be them causing it

 

[v6nutz_2012]

I doubt it will be the regulator, but if it was stuffed, it would cause problems. I'm not sure about checking the regulator in the VP, but in my car I just remove the vac line from the regulator with the car running for about 90seconds, if you get a little fuel coming out, then its gone.

I wouldn't be surprised if it is the plugs. I had the same problem so I changed the plugs/leads and it fixed it. Turned out that the mechanic had put the wrong plugs in (had n/a plugs in rathert than the l67 plugs, and they were gapped to 2millimetres!!!)

Anyway good luck and let us know how you get on.

When I look at the car next, i'll disconect the vac hose and see what happens
The last person to do the plugs was me. Leads were changed at the same time. Can't remember what plugs I used but they were recommended for my car. Any recommendations as far as plugs go? Part No.?
Thanks for the help guys, much appreciated

 

[Brett_jjj]

They were second hand ones off a VS, that car ran fine with them though so would be unlikely to be them causing it

If the plugs and leads are new, then Id be fitting 3 new genuine coils, as old second hand coils could be on their last legs or even just as bad as the ones youve replaced. Testing these coils with a multimeter can be misleading too, as they dont always show up as being faulty when in fact they are.