Solve my mystery

[Jinx]

The Problem:
Engine bucks at low RPM (forward & reverse) and sometimes stalls alltogether.
Usually difficult to start after sitting a couple of days.

The Info:
1994 Mustang GT / automatic transmission (my moms)

KOEO = 111
KOER = 111
CM = 10

This is why I need everyones help. The codes come up clean, but the car still runs weird. Is it emissions, fuel, electrical, or something else?

 

[DaveB]

When was the last time the car had a tune up? Sometimes its simple things like the O2s or plugs and wires that cause problems like that.

 

[BlackVert]

clean the mass air meter sensor wires
clean the intake air temperature sensor wire
change the fuel filter
change the distributor cap and rotor
change the spark plugs and wires

 

[Jinx]

clean the mass air meter sensor wires
clean the intake air temperature sensor wire
change the fuel filter
change the distributor cap and rotor
change the spark plugs and wires

Still having trouble

MAF cleaned
distributor and rotor new
plugs changed in '91

According to her, the vac line to the Evap purge valve had melted through. I replaced the vac line and re-attached the valve to the back firewall. Could the valve be damaged and causing this?

 

[kck6894]

One of my friends had an Escort that did the same thing. The Air intake tube between the air-flow meter and the Throttle body had a hole it. As soon as I sealed the hole up it stopped. Make sure you check for leaks between the AFM and the THB. You might get lucky and it's something simple like that.

 

[CManT1914]

One of my friends had an Escort that did the same thing. The Air intake tube between the air-flow meter and the Throttle body had a hole it. As soon as I sealed the hole up it stopped. Make sure you check for leaks between the AFM and the THB. You might get lucky and it's something simple like that.

wtf is an "afm" and "thb"?

 

[Jinx]

Update

She had the car at AutoZone. They tested the battery and the Alternator. They both came up good. He suggested the difficult starting could be due to loose wire to the starter or corrosion within the wire.

 

[BlackVert]

plugs changed in '91

time to change the plugs.
change the wires too.

 

[BlackVert]

wtf is an "afm" and "thb"?

afm = air flow meter ??
thb = throttle body ??

 

[CManT1914]

afm = air flow meter ??
thb = throttle body ??

Oh yea, Jinx, did you mean the wires were changes in 01? Cus your mom's stang wasn't even around in 91.

 

[musclecarmaniac]

I have never personally cleaned mine but i have heard that the Iac (idle air control vave) can cause this

 

[mootang]

i say change the plugs and wires and possibly the coil.

also change the fuel filter

 

[kck6894]

afm = air flow meter ??
thb = throttle body ??

Sounds good to me! Those are the codes we use at work. Sometimes I forget nodboy knows what they mean.

 

[Jinx]

Oh yea, Jinx, did you mean the wires were changes in 01? Cus your mom's stang wasn't even around in 91.

Oops I did meant '01 for the plug change.

i say change the plugs and wires and possibly the coil.

I'll suggest that to her, but she's running a separate coil/distributor not a coilpack like on mine. so I'm going to take it that you mean the separate coil

I found out that her + battery cable had corroded a while back and instead of replacing the whole thing the shop (butchers) just cut it after the corrosion and spliced on a new 12" lead to the terminal.

From what I've seen so far:
New main power wires (battery to soleniod to starter)
New plugs
New fuel filter
Clean IAC valve (possibly buy new)
Possible new coil, dist. cap, and rotor?

 

[Pokageek]

Typical BAD EGR valve. My bet.

 

[Jinx]

Typical BAD EGR valve. My bet.

Possibly, but wouldn't a bad EGR throw a code for insufficient flow??

 

[CManT1914]

Oops I did meant '01 for the plug change.

I'll suggest that to her, but she's running a separate coil/distributor not a coilpack like on mine. so I'm going to take it that you mean the separate coil

Right, the coil on hers will be on top of the power steering pump bracket. Extremely easy to replace.

Possibly, but wouldn't a bad EGR throw a code for insufficient flow??

Most likely, but it's possible that it's not. As long as a sensor is still within it's range of operation, then it won't throw a code. But it can be "on it's way out" so to speak, and not be functioning very well, but still be "operational" so the computer won't throw a code. This is what happened to me when one of my MAF's went out. I ended up just having to test every sensor I could find, MAF, IAT, IAC, TPS, O2's etc. etc.. Finally just replaced my MAF with the Pro-M i had sitting in my toolbox, and BAM! had all my power and mpg back.

 

[a50sn95]

I found out that her + battery cable had corroded a while back and instead of replacing the whole thing the shop (butchers) just cut it after the corrosion and spliced on a new 12" lead to the terminal.

FWIW, Have you seen this wire (harness) on our cars? It's not just a simple wire like the old days.
There is no aftermarket replacement, and from the dealer list is over 320.00
Sound like they did the only thing resonable.
You'll have to split the harness and separate it all out to change out that one wire. They'd probably charge you more than the 320.00 just in labor to do that.

 

[a50sn95]

I found a picture...:
battery cable

 

[Jinx]

Thanks for the link and the pic.

I'm not upset that they didn't replace the whole cable (I saw some prices from Ford ) IMHO they should have clipped the corroded lead back far enough (on both ends)and just left it in the harness, then ran a new cable (whole) from the terminal to the starter and zip-tie it to the harness.

I will print all the thread, so far, so she can read it and form an opinion as to what she wants to start with first.