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rough idle/surging after start...stumbles when driving

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Old 12-05-2004, 04:04 PM
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Default rough idle/surging after start...stumbles when driving

I posted about my g'friends 95 ssei the other day and wanted to thank all for there responses. I am starting a new post so we can solve the most important issue first. (drivability)

I started the car this morning and after a few seconds it began to idle erratically. I drove to the parts store and was able to get it scanned. these are the results: current code p0101...history codes p0101,p0171,po571,p0626 and p0629.

I have replace the MAF several weeks ago because p0101 was consistently present. At the same time I tested the connector for proper control voltage and 12v. After that I replaced the O2 sensor because of a bank 1 lean code. The car still ran like a pos so my g'friend took it to the dealer. They said it had a bad MAF sensor. We picked it up and I put another MAF sensor in it. It ran alright for a couple of days exept for an apparent ign. breakdown/ stumble intermitently. The other day I parked it for 10 minutes and when I tried to start it started and died immediatly about 5 times in a row. I nocked on the MAF and wiggled wire connections on various sensors and tried again and it started and I drove it home and haven't messed with it til today.

Now it has a p0101 trouble code again. Is it possible that NAPA sold me a wrong MAF sensor for this car? What else could cause a P0101?

I have had the battery disconnected for the last half hour. I am now going to go back to the auto parts store if it throws another code and have it scanned again.

BTW- this all started shortly after I replaced the water pump. Could I have done something to cause this problem?

Thanks for all the help!!!!!

Rob
Old 12-05-2004, 04:07 PM
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You're going to have to shoot the MAF wires back to the PCM. Suspect intermittent short or break.

Someone with an FSM get in here and give him some pin positions please?
Old 12-05-2004, 04:52 PM
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Originally Posted by Damemorder
You're going to have to shoot the MAF wires back to the PCM. Suspect intermittent short or break.

Someone with an FSM get in here and give him some pin positions please?
I am going to give the wires a good look where they pass the altenator and everything in the area where I worked on the water pump. Is the PCM located in the passenger side kick panel on this car?

Thanks Damemorder!
Old 12-05-2004, 05:08 PM
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Yup, You can see it right up there under that dash.

Try using an ohm meter and watch the readings while you move the wires around.
Old 12-06-2004, 03:04 PM
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My Fluke meter is gone. I guess someone thought they needed it more than me.

I pulled the batt. neg. yesterday for about 30 minutes. I removed coil packs and cleaned terminals with contact cleaner, loosened, wiggled and tightened fender grounds, and rechecked all sensor connectors.

I drove the car for about thirty minutes and it ran perfectly. Shut it off for an hour and drove another fifteen minutes. Perfect!!! Since I don't have a VOM or the pinout for the MAF I let the car idle and wiggled the MAF connector and wires leading to the PCM hoping I could get the car to act up again. No luck.

Today I started the car up and it idled perfect. I left it to warm up and when I returned I had a check engine light. The car still was running perfect. I drove it around for thirty minutes and it ran flawlessly. I went and had the codes pulled and had another p0101.

Any Ideas???

Thanks,
Rob
Old 12-06-2004, 03:46 PM
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When was the last time plugs and wires were changed. Our '95 was doing the same thing and even dropping cylinders and setting the engine light. Just put in new plugs and MSD wires, and now it runs like new again. Old plug wires DO NOT like to be moved, they "fritz out" internally. Also happened with my '96 Park Ave. Same problem, same cure.
Old 12-07-2004, 04:44 PM
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Originally Posted by cadmanspd
When was the last time plugs and wires were changed. Our '95 was doing the same thing and even dropping cylinders and setting the engine light. Just put in new plugs and MSD wires, and now it runs like new again. Old plug wires DO NOT like to be moved, they "fritz out" internally. Also happened with my '96 Park Ave. Same problem, same cure.
The plugs were changed a year ago and the wires may have never been changed. I am guessing they have 8000-10000 miles on them. She drives very few miles, the car only has about 70,000 miles on it. Do you know what code was thrown when this happened?

Thanks,
Rob
Old 12-07-2004, 05:23 PM
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I don't recall the code... Just that it kept setting the light. The wires and plugs on ours were only a year old and they were toast. At least 3 were bad. Miles aren't the only factor, as age takes it'* toll.
Old 12-07-2004, 05:39 PM
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Age is more of a factor than miles. Replace those things pronto, bud. The Belden wires from NAPA have a lifetime warrenty, and I haven't heard anything bad about them [yet to try them myself, since my engine is in pieces, and the plug wires are the least of my worries ]. Get some NGK TR60'*, and gap them at .60. I have original wires on my car, and I had over 2,000 ohms resistance on even the shortest wire. I do not even know how the hell they even worked. Just keep that in mind . I have a 16 year old car, with 150k miles.. just in case you didn't know.


-justin
Old 12-08-2004, 01:38 PM
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Also, check your vacuum lines. I had a surging problem that was related to those as well. Minute cracks (age again) develop, and if anything is moved around near the Throttle Body those lines split and leak. In that instance I replaced all the lines that were even close to suspect. After codes were cleared car was very "happy" and ran fantastic ( at least until the plug wires fritzed).


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