3.4 bucking on acelleration under load

[Daggar]

As long as the car is idling it's happy it runs great. But once you get it going on the road and get to a crusing speed it wants to buck if you go more the 1/4 of the way on the pedal. Has anyone expirenced this before?

[ns87]

Not on a 3.4, but for me it was a dying fuel pump (twice) Try the fuel filter first, but I wanna bet on fuel pump

[Andrew]

yeah check your fuel pressure at the rail, then if that is fine, fuel injectors need tested.

[CNBZ34]

If you have any access to a hand held labscope, I'd do a sweep test on your TPS and make sure you do not have a flat spot on it. That's if you experience this at the same throttle level consistantly. Can you get past it? meaning if you matt the throttle does it still do it?

[Daggar]

I can get past it a free idle with the clutch in or if it sits at idle in neutral. Otherwise I can't put the hammer down. It still shakes at 4k rpm +

[Z34-5speed]

Had a very similar thing happen with my LQ1. For me it was a combination of a misfire from bad plugs/wires and a bad o2 sensor.

[Daggar]

Wow this was the cheepest fix yet on my Z34 lol. Stupid vac line came off the vac ball under the front fender. I put that back on and wow what a diffrence. I still notice a a little bit of a rough acelleration some times. So I'm gonna probably do a tune up on it and you think I should replace the coil packs cause they are 13 years old?

[Psych0matt]

couldn't hurt, but if they arent failing then I wouldnt bother plus, they're a pain to get to