runs rough then dies

[kzbill]

91 festiva L EFI 5 spd.
the car starts to run rough and loses power, check engine light comes on, then when I stop it quits.
I then proceed to pull the neg. battery cable let the computer rest a few seconds. hook up the cable and everything is fine for 50 mi. or so.
then back to the same problem.
new ignition parts, the sea foamand lucas injector cleaner seemed to work fine.
I am thinking O2 sesor, but would that actually make it quit.
also if it is still running in nuetral when this happens I can push on the accelerator pedal and it tries to die til I let off.
Stumped for now!
Bill L.

[funky technician]

ya, I'd say O2, that pretty much the only thing on these motors (other then catastrophic failure) that throws a code, and yes it will stall with a failing O2

[kzbill]

Ohh too

hmm...... sounds like the first thing to check, I have done all the other stuff and it drives like a fairly new car. Aspire brakes and vac booster, aspire springs and hubs all around, (little height, and a pickup truck ride), 13" blizzacks, new stereo, new carpet, low mileage motor and trans, new gaskets and seals, it was an AZ body with about 160,000 to start with. I have had everything off and back on.
Thought I may try to cheat on the O2 sensor, so I took the best looking one I had. Maybe a bad choice.
I guess an O2 sensor will be toward the last of the things to replace.
I even changed the fusible links with circuit breakers.
got the fan fixed, and so many other things after two years of part time fiddling to get it back on the road. Now almost every part of the entire car will be rebuilt or replaced.
Reading the posts on here has been a great resource. I have even started rebuilding frt wheel bearings and hubs for others.

[TominMO]

ya, I'd say O2, that pretty much the only thing on these motors (other then catastrophic failure) that throws a code, and yes it will stall with a failing O2

The O2 sensor is a one-wire type, I guess. Bosch makes a generic one for $25 or so, at any parts store. But I would be surprised if a failed O2 sensor would make the car stall. I would think it would just go into a default limp-home mode which would still be drivable. But I bow to superior experience if such is the case. If a code is being given, check to see what it is. Is there a code list anywhere at FF.com?

I would be more inclined to suspect a malfunctioning MAF sensor (mass airflow sensor) or TPS (throttle position sensor).

[funky technician]

I would be more inclined to suspect a malfunctioning MAF sensor

actually, thats another good posibility too

[kzbill]

gone over the TPS twice and it is set right and seems to operate properly, the MAF is out of a "known good" festy I have another MAF I may try that after the O2 sensor. The sensor has lots of mi. on it maybe 160,000 so it may not hurt to replace that anyway. when I started the car for the first time it fouled about two sets of plugs til the injectors cleared up, may have fouled the O2 also.
I have no way to read the codes and it only happens after running for an hour or so. I was thinking fuel but then it wouldn't clear up as soon as I reset the computer.
After 2-3 yrs of waiting I can wait another week or so to get it right. I really appreciate the help I have gotten here I don't have a "real Job" right now so DIY is my only chance.

[kzbill]

I just went over the problem with another festiva enthusiast so now two of us are confused.
The car did do what I described while he was here so all could be checked we agreed that the O2 sesor probably wasn't defective and it ran with it disconnected just fine. took the cover off the TPS and that was functioning as it should. Had the cover off the VAF meter all seems to be operating smoothly. checked the connections too. My friend suggested the computer because of the intermittent nature of the diease. so I am going to swap that out later and give it another try. I have another VAF so if worse comes to worse I can try that too. I already ordered an O2 sensor and it isn't a bad Idea to replace those from time to time anyway.

[Blaster2005]

runs rough then dies

I would replace o2/oxy sensor! After replacing the one in my 93 Festiva, I noticed more power and more miles per gallon! It may also be your TPS sensor, Mas air flow sensor or your coolant temp sensor. The coolant temp sensor can cause a lot of head aches!

I replaced my o2 sensor with a Bosch from Auto Zone. I bought the cheaper one and spliced the wire.

Hope this helps!

[kzbill]

Does any ne know the TRUE FUNCTION of the 5th gear swith, AKA: nuetral saftey switch, AKA: PNP switch, AKA; transmission position sensor located on the bottom side of the trans????

[festivaWES]

I'm alomst 99% sure its the O2 sensor mine did the same thing when i did my b6-e swap with a old oxygen sensor in there. Went to autozone and picked up the one wire universal, and it ran way better

[kzbill]

well it seems OK now! drove it 50 mi with no problems surfacing.
It seems that the neutral safety switch on the Manual trans. is more of a sensor telling the computer it is in 5th gear. seems strange, it is "my bad" of course, when the engine wouldn't start I read in the manual about the "nuetral safety switch" and I couldn't get continuity I "ASSumed" that the switch was not functioning. (it was the connector) so like with any "nuetral safety switch I bypassed it. by bypassing it the computer thought it was in fifth all the time, Somehwere I read, or so I remember, that told the EGR to operate.
That was causing a code. the engine light would come on and all was bad.
This Diagnosis is assumed also because I think it may take more driving to make sure this doesn't happen again.
Thank you everyone for your Ideas, and thanks to the site for a treasure trove of advice and knowlege.

[GenevaDirt]

I unplugged my switch a few hundred miles ago and have had no codes or problems with the way it runs. At least the one I unplugged was under the dash by the clutch pedal....hope yours is still running good.

[kzbill]

Thanks,
mine is the other plug, in the engine compartment, that ges to the switch on the passenger side of the trans, above the crossmember.
The main problem was jumpering it when I needed to just fix the connection.

[kzbill]

Happened again! this time had a loose ground on Battery, never happens here so I can find it just happens on the road where I have to reset the computer and drive. other than that it runs really sweet.

[kzbill]

turned out the Distributor was bad after all that. I am glad because by checking and fixing or replcing everything else I am now very confident in the car and my ability to fix any future problems. The side benifit was being able to Identify as good my spare parts that I swapped to test it.