engine stuttering...driving me insane

[black5.0]

ok guys, i really need your help here. my car starts to stutter when im driving around at low rpms giving it minimal gas like its gasping for air or something. its actually more like its bucking from making a bad shift. the front end dips and bucks back up until i either let off the gas or give it more gas. anyway, the weird thing is that it only happens when the engine is warm. everything is fine when its cold and at WOT. ive changed the fuel filter, changed the spark plugs, cleaned the iac, checked the tfi module...and its still stuttering . i really dont know what else to check, its driving me insane. im just hoping its not the tranny. if anyone has any idea of what it could be please let me know. thanks in advance.

- Joe

 

[Ambizzy]

Checked the O2 sensors? That's what it sounds like to me.. Also have you run any diagnostics on it?

 

[noslow5_0]

yeah i would dump the codes, an find out whats going on... can be anything... stuttering or bucking is usually a lean condition. also are you getting any poping thru the intake??? fuel pressure, o2 sensors an any vacuum leaks are 9 times outta 10 the problem that causes this. to dump the codes, do a search for dumping codes as jrchker (cant remeber his name) has a good right up on it. Good luck!!!

 

[black5.0]

ok i did a search and found some interesting stuff about the o2 sensors. i guess if they are bad then your gas mileage goes down the tubes. well my gas mileage is horrible, i get about 200 miles to a tank. but would they make my car buck like its been doing? and no i havent run any diagnostics on it....

 

[black5.0]

and how would i go about replacing the o2 sensors? are they expensive? where are they located?

 

[black5.0]

bump

 

[trips52]

ive been runing no o2 for a year now... and never had any prob.....

 

[Ambizzy]

Mustang O2 sensors are in the pipe, just past the header to pipe connection. You're gonna have 2 (bank 1 and bank 2) and you should be able to find some OEM sensors for around $50 - $80 or so. Make sure they're 3 wire terminated!
You could check them yourself to see if there's any carbon build up, and you're right about the gas milage. Since these sensors 'read' the amount of oxygen that's in the exaust sends it to the EEC then compensates the fuel correctly.
Check 'em out and see if that's the problem. You're lucky you don't have a 3.8 like me, there's 4 sensors and I had to replace them all about 3 months ago!

Good luck and I hope I helped a little
Amber

 

[cjman15]

Mine seems to do tha same thing... bucks and pops like it's getting choked out... Mine does it more when it's cold tho... but i know exactly what its like

 

[LX302]

When was the last time you did a tuneup on the car?
Bad Oxygen sensors wouldn't let the car buck and surge that violently.
A good set of plugs, wires, cap and rotor, cleaning the throttle body might clean up this problem. It also could be a bad TPS sensor.
Scan for codes after the tuneup before you start replacing any sensors.

 

[black5.0]

what is a tps sensor?

 

[Spyderd68]

TPS = Throttle Position sensor, it sits on top of your throttlebody(plastic thing with a green and orange wire coming out).

Dave

 

[K.C.90gt]

i had this problem on my stang when it was cold mostly. I found that by turning down the fuel pressure it got rid of it completely. So I would check out your fuel pressure and adjust that up and down if you can to see if the bucking changes. This was with a blown motor though so it could be different, oh and I'm still waiting for dyno tune to see my A/F mixture.

 

[25thmustang]

What about if the car runs perfect and then begins to do this after about 30 mins? Would it be the same sort of thing?

 

[K.C.90gt]

What about if the car runs perfect and then begins to do this after about 30 mins? Would it be the same sort of thing?

it could be related that way, the car runs richer when cold and could be leaning out too much when it warms up. Then again it could be related to other things. There are a lot of different variables that effect timing and even fuel pressure which are usually related to the causes of the car bucking. ie, bad/faulty sensors and/or parts. Me personally though found that by adjusting the fuel pressure it effected that bucking at low rpms a lot, so its worth a try in my opinion.

 

[black5.0]

it was the tps sensor. i went to autozone today because they run that free computer check. the test came up that i had a bad tps so i changed it and now she runs perfect. thanks to everyone that helped!!