Rough idle, intermittent missing

1slow95 · Jul 9, 2006

This car's really starting to piss me off again. It's idleing kinda rough now, like it's missing or something. It also has a miss while cruising that's completely intermittent, and at around 5800 when accellerating which is also intermittent. I've also had a problem with the car cutting out while cruising. It'll be running nice and smooth, then it's like it looses all power for a second. I just changed the fuel filter and spark plug wires, everything else on the engine only has about 1500 miles on it, except for the ACT, ECT, and coil which are a couple years old.

I think I may borrow a coil today and see if that helps. If not, could it be an electrical issue? I know my battery cable does not have a very good connection to the fuse box(small wire, battery in trunk). I've been meaning to fix that but I've been to lazy.

One more thing to thing, the wires to one of my O2 sensors got cut, and the car seemed to idle better after that and driveability was a little better.

WhiteDevil · Jul 9, 2006

Damn mine did the same thing when i had a burned plug wire grounding out on the header. But it looks like you got some new ones.

SeventyMach1 · Jul 9, 2006

So your o2's are new?

It doesn't sound right that it would idle better after being cut. Something may be wrong there.

HISSIN50 · Jul 9, 2006

Any codes?

Is the EGR hanging open a hair?

If it's rough at idle, I'd run a cylinder balance test while you pull codes. It really helps narrow down misses that arent blatently easy to spot.

Good luck.

1slow95 · Jul 9, 2006

O2's are new. They're made by Bosch I think, got them from Advance or Auto Zone, I can't remember which one.

I don't have EGR . It was supposed to be turned off in the computer when I had it tuned, but when I unplug the sensor my CE light comes on. Is that normal? Right now I have the sensor plugged in and the plunger held halfway in.

How do I run a cylinder balance test?(too lazy to search at the moment ) Is there a way to pull the codes without a scanner? My connector fell onto the header and kind of melted...

This is an old video from before the tune, but you can kind of hear what it's doing.
Right-click, save as...1.6MB
http://highoutputgt.homelinux.net/movies/stangclip2.wmv

1slow95 · Jul 11, 2006

HISSIN50 · Jul 11, 2006

Low-5.0 said:
O2's are new. They're made by Bosch I think, got them from Advance or Auto Zone, I can't remember which one.

I don't have EGR . It was supposed to be turned off in the computer when I had it tuned, but when I unplug the sensor my CE light comes on. Is that normal? Right now I have the sensor plugged in and the plunger held halfway in.

How do I run a cylinder balance test?(too lazy to search at the moment ) Is there a way to pull the codes without a scanner? My connector fell onto the header and kind of melted...

This is an old video from before the tune, but you can kind of hear what it's doing.

I'm obviously not a tuner, but if the EGR is turned off, how is a CEL triggered (it's triggered by something the computer shouldn't know exists)?

Check your repair manual or code reader instructions for CBT instructions. You do the test after pulling KOER codes, and it involves goosing the throttle (I also have to check the instructions when I do the test - otherwise I'd type out the wrong instructions.).

With your nice combo, that's the best I could think of.

Good luck Mike.

rio95 · Jul 11, 2006

Check the wires even though they are new. I have the same problem from time to time and taking them off and putting them back on usually does the trick.

Also, check your tps.

Black95GTS · Jul 11, 2006

Low-5.0 said:
O2's are new. They're made by Bosch I think, got them from Advance or Auto Zone, I can't remember which one.

I don't have EGR . It was supposed to be turned off in the computer when I had it tuned, but when I unplug the sensor my CE light comes on. Is that normal? Right now I have the sensor plugged in and the plunger held halfway in.

How do I run a cylinder balance test?(too lazy to search at the moment ) Is there a way to pull the codes without a scanner? My connector fell onto the header and kind of melted...

This is an old video from before the tune, but you can kind of hear what it's doing.
Right-click, save as...1.6MB
http://highoutputgt.homelinux.net/movies/stangclip2.wmv

If you're CE comes on after taking your EGR out, then your computer (assuming you are running the T4MO still) is looking for EGR. This could cause any number of driveability gremlins, not to mention an increased propensity for the car to ping.

As a TwEECer user, I know that we can defeat the CE light two ways:

1 - Turn the CE light off.
2 - Tell the computer that no EGR is present.

Adam

OrangeMustangGt · Jul 11, 2006

i have a post up now of the exact same problem....And i replaced Everything......except my plug wires......Maby get a cheap set from autozone, and if it fixes it or not, return them....

As far as the egr, i've had no problem by keeping mine half-way in. I used a little brass fitting with a hose clamp around the whole thing.

Let me know though because like i said, my car is having the same issue, and its WAY down on power.......sucks

1slow95 · Jul 15, 2006

Bump.

I checked my plug wires and found one that might have been causing the problem, but I replaced it with an old one and it still does the same thing. Could it be spark plugs? Right now Im running Autolite Racing (sidegapped) plugs gapped at .50. What should the gap be set at?

I'm going to work on it later today and try to fix my battery wiring and a couple other things. I'll post up results tonight or tomorrow.

95Vert · Jul 15, 2006

I really doubt it's your EGR, especially since it just started doing it. Mine would do this and I also replaced everthing but the plugs. Once I replaced them, the problem was gone. On my previous mustang, it turned out to be a bad ground to the battery. It wouldn't hurt to run an extra cable to the block.

1slow95 · Jul 15, 2006

Ok, I got a GOOD video of exactly what it's doing. I'm pretty sure I fixed my power wire problem, but I could still have a bad ground. I'll work on changing the plugs and maybe pulling the codes tomorrow.

Right click, Save as.
Rough idle - 984kb

1slow95 · Jul 16, 2006

95Vert said:
I really doubt it's your EGR, especially since it just started doing it. Mine would do this and I also replaced everthing but the plugs. Once I replaced them, the problem was gone. On my previous mustang, it turned out to be a bad ground to the battery. It wouldn't hurt to run an extra cable to the block.

I must have forgot to mention that this is not a new development, it's been happening for a while. I've just been too lazy to try to fix it.

I have my ground wire connected directly to the engine. Do I still need an extra cable from the engine to the chassis?

I just pulled the codes, here's what I got:
511 - EEC processor ROM test failed
334 - EGR closed voltage higher than expected
565 - Canister purge circuit failure

All three showed up twice, and the 334 code showed 4 times total.

I may get around to changing the plugs here in a little while...

95Vert · Jul 17, 2006

I have one to the block and another to the chasis. Better safe than sorry.

On that canister code, if it's the one in the fenderwell, unplug it and see if it does anything. Gcom,(paul) had some problem with that but his car smelled a lot like gas.

1slow95 · Jul 17, 2006

95Vert said:
I have one to the block and another to the chasis. Better safe than sorry.

On that canister code, if it's the one in the fenderwell, unplug it and see if it does anything. Gcom,(paul) had some problem with that but his car smelled a lot like gas.

It is unplugged, which is probably why Im getting that code.

95Vert · Jul 17, 2006

Oh, that's right, you got rid of all that crap.

95Vert · Jul 17, 2006

Mike, it had gone over my head, but do you have any vaccuum leaks? The reason I'm asking is cause a buddy's car was also sputtering and we checked all sensors and such, we ended up spraying carb cleaner around the intake, and there was a vaccuum leak. Just a thought.

1slow95 · Jul 17, 2006

I'll add that to my list of things to check this week. Thank's for the help.

BlackVert · Jul 17, 2006

i had the same symptoms ... mine turned out to be 2 bad wires ... damn equal length shorty headers burned them up

Rough idle, intermittent missing

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