What can cause bucking below 2k rpm?

[OrangeMustangGt]

if this helps anyone....a follow up.

After throwing all kinds of money at this issue, i was correct in that it was spark related.

I ended up buying new plug wires, cap, rotor, playing with timing, ect.

As of now, the problem is 100% cured.

Turns out that i had my plugs gapped WAY to low......025......I re-gapped some new plugs to .040 and pow....problem solved! Also, note that initially when i put the plugs in gapped at .025 the car was fine but it turned ugly quick....almost undriveable.

SO, if anyone is having this issue, look first at your coil, cap/rotor/ wires and plugs, if your car was running OK, before this issue occurred that is most likely your problem, one of the above.

Btw, my bronco was doing the same thing, and it turned out to be bad wires.

 

[fawcett]

I had this problem, it went away when I had a full Mallory Digital Ignition system installed.
FYI, the problem persisted until I finished the system with a new coil and distibuter. With everything new she runs pretty smooth, even untuned. I also cleaned the MAF which made the idle smoother and almost stopped that annoying idle surging.

My idle floats from 1000-1200rpms, any lower and there is not enough vacuum for me to turn the steering wheel (without throttle applied). I do still blip the throttle when I am turning at a stop or at slow speed because the rpms drop and she occasionally wants to stall. Damn that e-cam with our 94-95 stock EMU's
-fawcett

 

[stangGT97]

Dirty or broken MAF sensor element(s). This happened to me and was fixed after I replaced the MAF sensor.

I'm a 4.6 guy but I'm having the exact problem that is described here. The MAF is just about the only part of my electrical system that has not been replaced. How do you know if the MAF parts are broken? Are the sensors physically damaged, or is it something you can't see with the naked eye.

GreenMustangGt, good to see you fixed your problem. So far I've replaced my whole ignition system and a whole host of other sensors and filters and I'm still getting that low rpm buck that you had. Oh btw, I have a house in cape cod, I'm from the Boston area (but relocated to Ohio temporarily)

 

[JJ95GTID]

When I cleaned the original MAF wires I thought I was being super careful. The wires looked fine but apparently I bent one enough to break the glass coating on the wires.

 

[OrangeMustangGt]

GreenMustangGt, good to see you fixed your problem. So far I've replaced my whole ignition system and a whole host of other sensors and filters and I'm still getting that low rpm buck that you had. Oh btw, I have a house in cape cod, I'm from the Boston area (but relocated to Ohio temporarily)[/QUOTE]

oh wow, nice to meet you. Where on cape cod? I'm in Marstons Mills.

Before you replace your maf, try cleaning it with some rubbing alcohol and a q-tip, that may fix the issue. Also, have you tried changing the spark plugs and verifying gap? that is what my problem turned out to be......But, who knows about those crazy modulars, it could be having an emotional problem for all you know.

 

[Therian]

cleaned my MAF, plug connectors, coil connection and dist. connections. idle actually dropped from 1000-1100 down to a very nice 750. I'm still getting a CE light that causes the rpms to shoot up...but once the car is driving the idle is no longer affected. Car no longer bucks.

still gotta run codes though to figure out why the engine is being fussy.

 

[stangGT97]

oh wow, nice to meet you. Where on cape cod? I'm in Marstons Mills.

Before you replace your maf, try cleaning it with some rubbing alcohol and a q-tip, that may fix the issue. Also, have you tried changing the spark plugs and verifying gap? that is what my problem turned out to be......But, who knows about those crazy modulars, it could be having an emotional problem for all you know.

the maf has been cleaned and plug gap is correct. You're probably right, it's just PMSing haha.

My house is in Dennisport btw. I'm not sure where Marston Mills is though