bucking is driving me crazy

[tsupra]

using a smooth idle as a way to tell if you have a vacuum leak is a poor idea. you have more vacuum at partial throttle and wide open throttle than at idle. with more vacuum, a crack in a hose can open that would stay closed at idle. it's the same with a crack or loose connection in your intake piping.

[memories83]

I vote for fuel pump.

[maximaj30]

blah theres too many things it could be lol

fuel pump would be a easy thing to change being external, that might end up being the next step. did yours act up only after it was driven for a while?

other thing that could make it the fuel pump is it stranded me the first time i drove it about a month ago, parked it for 5 minutes and came back and it cranked but wouldnt catch. after 10 minutes of trying it finally barely started

[suprafastcelica]

I could drive mine down the highway at 70. At some points the bucking would start and the car would slow down some times to 40 no matter how much petal i put into it.

[memories83]

You may also check the inline screen inside the fuel line on the inlet side of the fuel pump. If the screen becomes clogged it will starve the system for fuel and create symptoms very similar to what you are describing. Takes only 10 minutes to check. Worth a shot before spending money on a non-returnable pump.

[maximaj30]

I could drive mine down the highway at 70. At some points the bucking would start and the car would slow down some times to 40 no matter how much petal i put into it.

so thats the same thing, because a few weeks ago i took it on the highway and was at 4000rpm in 5th with no bucking

i'll check the screen first and then probably try a pump, thanks again for all the help. think i have it narrowed down now

[Snafu_Bohica]

Mine does it too. But more like in 5th gear cruising, if I go to accelerate it will seem to miss... But I have not been able to figure anything out. I replaced my good fuel pump with a good fuel pump when my fusible link broke... Please let me know what is up. I have the EXACT same symptoms.

[maximaj30]

oxygen sensor came today, gonna change that and see if it fixes it which i doubt and move onto trying the fuel pump i guess

i wish it was only 5th gear cruising, at its worst you can barely get going in 1st and it bucks literally like youre offroading a truck on a bumpy road. just want to get it going because since ive bought it a year ago ive driven it for fun pretty much only one night, otherwise its been fixing stuff which i dont mind but i want it running

[Snafu_Bohica]

i wish it was only 5th gear cruising, at its worst you can barely get going in 1st and it bucks literally like youre offroading a truck on a bumpy road.

I played with my timing (mine is MKII though, didn't notice where this was located until I went to find it after I posted) and got rid of my 4th gear bucking. Now it only bucks RIGHT when I start moving in first and between 2,700 and 3,000rpm in 5th... So it may just be your timing But I may be wrong... Probably am wrong, I'm a teenager.

[MK2P4NDEMONIUM]

Had a similar problem on my 96 Maxima, just randomly happened.
I replaced everything that I could think of from coilpacks, fuel filter, o2 sensor, tps, iacv(was having idle issues), and nothing was helping, that was until i pulled the crankshaft position sensor and found some metal shavings in it, cleaned it out and put it back in and it ran like it was brand new.

moral of the story: check your crankshaft position sensor.