Car is bucking and stumbling

R

red95gtconvert

New Member

May 29, 2006

382

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Ponca city, OK

Apr 23, 2007

#1

• Apr 23, 2007

• #1

Hello everyone, my car is acting up on me again. When I am driving at low RPM's the engine seems to stutter, randomly jerk and even buck every once in a while. The plugs, cap and rotor have about 5k on them and all of the plug wires are tight and snapped in to place. I have replaced all of the vacuum lines and everything else I can think of except the oxygen sensors. The thing is the car runs fine at full throttle so it is definatley a closed loop issue. Any input would be greatly apreciated. I hate to put parts on the car I don't need but the O2 sensors might be the next step.

 

C

cbarr300

Member

Jun 6, 2006

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goose creek, SC

Apr 23, 2007

#2

• Apr 23, 2007

• #2

try cleaning the maf yet?

 

angeljenylynn

New Member

Mar 31, 2007

20

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0

Louisiana

Apr 23, 2007

#3

• Apr 23, 2007

• #3

replaced the throttle position sensor?

 

1TallMF

New Member

Apr 17, 2006

955

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Montreal

Apr 23, 2007

#4

• Apr 23, 2007

• #4

Start with the free repairs such as was mentioned by cleaning the MAF. How old are your plug wires? I've had this problem 4 times now and it always ended-up being a bad or loose plug wire. O2's might not be a bad idea if you can't remember the last time they were changed, but that might not be the issue. Have you checked for codes yet?

Also, the fuel filter on these cars is something that should be changed regularly, like once a year.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Apr 23, 2007

#5

• Apr 23, 2007

• #5

The car is actually in closed loop at WOT AFAIK. Fox III's are what use a look-up table.

Any reason to think the PIP is an issue? At WOT and/or higher RPM's, a small miss or burb isnt as pronounced (perhaps not at all) compared to low RPM, where you really feel it.

Good luck.

 

The Green GT

No 13 year olds are safe around me.

10 Year Member

Jan 8, 2006

1,269

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99

Louisiana

Apr 23, 2007

#6

• Apr 23, 2007

• #6

I was gonna say to check the PIP too.

 

C

cbarr300

Member

Jun 6, 2006

746

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goose creek, SC

Apr 23, 2007

#7

• Apr 23, 2007

• #7

JT: I could be wrong when I say this...so hopefully someone more knowledgeable than I will chime in...but I believe the computer is in open loop mode at WOT. The computer does use some information gained from closed loop while in WOT, however. IMO, this is why it's so important to get an excellent closed loop tune before going to a WOT tune. It goes back to the saying, "Build a strong foundation." .... as do most things in life it would seem.

sorry to get off topic. I agree, if cleaning your maf doesn't help anything, and your wires are in good condition...I'd start looking towards the PIP.

Great information

 

R

red95gtconvert

New Member

May 29, 2006

382

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Ponca city, OK

Apr 24, 2007

#8

• Apr 24, 2007

• #8

Thanks for the tips, so far I've cleaned the mass air meter and checked extensively for vacuum leaks. One more thing to point out is the car has kind of a sketchy idle too. Can I try starting and driving the car with the O2's disconnected and see if idle quality/driveability improves? also where is the the PIP sensor at? is it located in the distributer? thanks in advance.

 

F

FeTTstang

New Member

Nov 21, 2006

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0

Apr 24, 2007

#9

• Apr 24, 2007

• #9

Could be your Idle air control sticking or failing to work.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

33

129

Apr 25, 2007

#10

• Apr 25, 2007

• #10

Follow-up thread with his solution:

http://forums.stangnet.com/showthread.php?t=697855

Excerpt of the opening post:

red95gtconvert said:

Hey folks I made a post a couple of days ago about how my car was bucking, stumbling, had random misfires, idled rough and just running like crap in general. Well the fix was changing out the oxygen sensors. The car runs smooth as can be now and feels like new again. Just thought I would let everyone know:SNSign:

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