Hey guys,

I pulled my codes today in hopes of tracking down a poor idle(won't idle when cold)/heavy miss on acceleration (in gear or not). This is what came out:

KOEO

23 TPS out of range during test
34 PFE/EPT sensor fault/High exhaust pressure

Continuous

34 same as above
67 NPS open with A/C on during test (I DON"T HAVE A/C)
95 no code listed on F-T website or in Haynes manual?????

KOER

23 same as above
12 cannot control RPM during high RPM test
13 cannot control RPM during low RPM test
72 insufficient MAP change during Dynamic Response Check
73 Insufficient TPS change during Dynamic Response Check
74 Brake on/off open
25 knock sensor not detected during Dyn Res Check
65 Key circuit low voltage

I was shocked and awed at the number of codes, so I ran each test twice and I got the same results for all on both tries.

What the heck should I test/replace first that will cure my idle/miss problem? Does anyone know why I got a code 67 and 95?

This is what has been done in the last week: new coil, Ignition control module, fuel filter, fuel PUMP, new plugs, wires, cap and rotor. Has a 3 month old muffler on it.

Hit me with your ideas! Sorry this post is so long,

Mike B

 

I would take the battery off for 1/2 hour and then run the truck for a week and test it again.

 

Will that wipe out all the codes? I thought I needed to pull the battery cable while it was testing to clear the codes. Do I do that first and then leave it off for 1/2 hour, or will just taking it off for a 1/2 hour do the trick. By the way, it misses so much that I don't know that I could drive it for a week.

I will try it,
Mike B

 

You've got at least 3 codes (12,13,23) which have to do with the TPS, which if bad will cause 73 and possibly 72.

Replace the tps and while you're out at the store getting it (in your other vehicle) leave the battery disconnected. install the new tps and then connect the battery. That should clear the old codes, and while you're driving around testing (you have to drive for a couple of hours total...doesn't have to be continuous) the computer will relearn the engine performance parameters and adjust to the new sensor. Also any new codes will be brought up and stored. Check codes in a week. then go from there.

Have no idea why 67 or 95.

 

Use a light water mist on the headers when sarting from cold to see if it is the same cylinder(s) missing. The ones that are running with get hot and evap the water quickly and the ones that are not will stay wet longer

67 can mean Neutral Pressure switch open, Clutch switch circuit failure, Neutral/drive switch open or A/C on, MLP sensor out of range or A/C on (E4OD)


95 can mean Fuel pump secondary circuit failure EEC to ground

hope this helps

 

Thanks everyone. I think I will change my TPS, but where is it. They don't have a good picture in the Haynes manual. Is it the sensor on the Back of the Throttle Body? Or the one on the top? (1990 4.9L) I tried to test both with my multitestor, but with out know which is which I can't tell if they are out of specs.

By the way the miss is definately random. Which sucks even more, than if it was the same cyls.

Mike B

 

I just replaced the TPS on my 95 302, and it was on the Throttle Body, on the bottom of it.

 

TPS for the 4.9 is on the back (or if your looking down the bores....to the right of the bores.) The one on the top is the IAC.
Clean that while your at it too.

 

Thanks Larry.

If that is true, then I am pretty sure that mine gave me readings out of specs. That will get replaced tomorrow night. Just a couple of bolts, right?

I will disconnect the battery tonight and throw it on the charger.

I will let you know what happens,

Mike B

 

I had a similar situation on an '88 Mustang 5.0. I recognize many of the codes you posted. I replaced the MAP sensor and the codes went away. The engine also started running much better.
Original symptom was poor/no idle and poor performance. Try to "borrow" a known good MAP sensor from another vehicle to test with. They are expensive to purchase new, especially if you do not have to have it. Once you know that you need it, search for the best price. Good luck.

 

Re: code 67
Refers to the neutral-park switch attached to the trans. ( About @29 at Autozone.) Often the NPS needs only a good cleaning. Its location exposes it to dirt and oil. When this code showed up I went underneath the truck and blasted the NPS with paint thinner driven by air pressure. The code never showed up again. And the transmission shifts quite smoothly. Try cleaning the NPS first before you invest in a new one.

 

A lot of sensors and such can just be cleaned when they error.
This can sometimes fix the problem.

 

Code 95-Fuel pump secondary circuit failure- PCM to ground
Code 67-Neutral/drive switch open or A/C on
Code 67-Clutch switch circuit failure
Code 67-MLP sensor out of range or A/C on (E40D)
Code 65-Overdrive cancel switch open, no change seen (E40D)


Thats what Chiltons has on your codes

 

OK, here is where I am at. I unhooked the battery and let it sit for 8 hours while I was at work. (took the other car to work) I put a new TPS on at 5:00. No change in condition. It actually seemed worse. I then took the IAC off and cleaned the hell out of it. Still wouldn't idle with out me feathering the gas, and if I hit it hard it would miss on every cyl. and just about die until I let back off the throttle. Then it wants to die until I start to feather the gas again.

So I got pissed and decided to take it for a drive and pound the crap out of it. I couldn't get the truck over 30 mph and when I would slam on the throttle it would bog way down and then buck and jump around until I let off. It was like this for about 10 min. Then it died while I was turning around. I restarted and it still ran like junk. Then I heard a whine come from under the hood for about a second and then the truck ran great. Ran like a watch, idled great! No misses! I was excited! Then I got home and let it idle some more in the driveway. With everything looking like it was fixed I shut her down.

20 minutes later I went out to see if I was dreaming, and it turns out I was. I couldn't get it to idle again without help. And it misses just as bad as before.

So I pulled my codes. It seems like they weren't erased by the battery being disconnected. They were all the same. So now what??????????

Any help at this point is greatly appreciated!
Mike B

 

i'm wondering bout that code 95 myself Secondary fuel pump circuit maybe your fuel pump is cutting out on ya

thats a good place to find codes as well