Stuttering/Bucking under very light acceleration

[theomajigga]

Hey guys,

I've got an issue that is driving me crazy. Searched a bit and just want to see what you guys think.

Open loop: No issue./ No bucking.
Closed loop: Under light acceleration the (10-15%) the car bucks like a pissed off bull. I can floor it @ a stop and it doesn't buck, just goes. It's driving the girl crazy and I want to fix it.

MAF?? TPS???

[theomajigga]

Just checked the TPS with a multi. Tested out fine.


So MAF???

[barnaclebob]

Thats what I would start with. I had abnormal throttle responses when mine was going bad but I also had left/right bank to lean codes. The car would lag and not have power, then the RPM's would surge as i pushed the pedal further. After it warmed up, this went away so I lived with it for awhile. Eventually it started losing power on the highway going up hills which was unsafe so I replaced the MAF. No problems since.


If you replace the MAF search on here for the thread which gives you the maxima part number, same thing for $120 instead of $400. My MAF had a dusty looking buildup on it that wouldn't come off so maybe if yours looks the same it is bad too.

[theomajigga]

Not the MAF. I unplugged it and it still acted the same. How many signals does the car get from the TPS? Does it use all of them?

[barnaclebob]

Not the MAF. I unplugged it and it still acted the same. How many signals does the car get from the TPS? Does it use all of them?

How does unplugging the MAF rule it out? I haven't heard of that before and am curious. I can't remember if I tried that or not when mine was bad.

[atraudes]

It's the same principle as trying to rule out a bad ignition coil. If you unplug it and the behavior doesn't change, the unplugged part is bad. If there is a change, it's at least partially doing its job

[theomajigga]

Bump.....

[bgruhn76]

I have 3.3L in my 2000...has distributor...does the 3.5L have one? I had same issue, and replaced mine. Fixed it right up.

[Hawairish]

Is it throwing any codes?

[theomajigga]

O2 code. And I don't think it has a distributor.... I guess I haven't had a look!

[barnaclebob]

Which O2 code...

[Buzzman]

I have 3.3L in my 2000...has distributor...does the 3.5L have one? I had same issue, and replaced mine. Fixed it right up.

No distributor in the 3.5L. Ignition coils.

Not the MAF. I unplugged it and it still acted the same. How many signals does the car get from the TPS? Does it use all of them?

You unplug the MAF in hopes that things change.
If nothing changes when you unplug the MAF, then that is your likely problem.