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Need help...I'm at wits end...


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I had the "loping" and engine miss symptoms along with P0101, P0171 and P0174. Changed the Plenum Duct. Now, car starts fine but idle stays at 2000 RPM. If I touch the throttle pedal the RPM goes up to 3K or 3500K and stays there. I see no binding of the throttle linkage. Sometimes it will "stumble and idle will go way down and engine will miss, then it will "jump" up to 2K RPM. Also I have a P0101 MIL code.

Does anyone have any insight into what the problem could be? Car is parked at friends shop and I don't have a clue as to next step??

Thanks in advance,

Dave

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P0101 - Mass Air Flow (MAF) Sensor Performance

Double check the MAF wire harness and connector pins and sockets.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Be carefull here; the wrong chemistry can damage the sensitive MAF components.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Just to be sure we are talking about the same connector (from Post #2), the MAF sensor connector on your 2000 model should be a 5 pin connector and the MAF sensor is in the intake air plumbing close to the air filter housing.

Also be sure the intake air plumbing between the filter housing and the throttle body is installed properly and secure.

And I have no idea what chemistry to use on the MAF sensor.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Right. Actually, that device delivers two signals to the PCM; one represents mass air flow and the other represents inlet air temperature.

The Service Manual for that engine has several pages of diagnostics for P0101 most of which requires a Tech 2 scanner.

Does the P0101 return immediately when you clear the codes?

And did you have a P0101 code before you replaced the plenum seal?

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Yes, I get an immediate P0101 as soon as I start the car.

Before I replaced the plenum I would have a P0101; then I would get a P0171 and a P0174. I sprayed TBI cleaner around the plenum and got the engine stumble and slight RPM changes so I concluded (from searches here) that the plenum was bad.

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If it was my engine, I would find a can of "O2 sensor safe" throttle body cleaner and spray the MAF sensor thoroughly-completely and allow to air dry before installing the intake plumbing. Avoid brushing - wiping or even touching the elements exposed to the air flow.

If that failed, I would probably throw a new part at it. Wonder if you have to buy the entire section of plumbing or can the sensor alone be replaced?

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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The sensor is part of the MAF, but I've got two MAFs (I bought one as a spare on ebay a year or so ago), so I'll try both, after cleaning.

Thanks again.

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"Replaced Plenum Duct...."

These will all go bad sooner or later. Anyway, high idle indicates a vacuum leak.

I think you fixed one problem but created another.

I dont think the MAF IS bad at all.

The intake gasket can be reused, that is, after it is inspected for nicks etc.

The gasket pads should be cleaned before reinstalling the intake.

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When you took off the intake to replace the plenum did you make sure the hose that runs from the center of the intake to the pvc valve was still connected? If you start the car and put your finger over that hose you should have vacuum, if you don't it is probably disconnected and causeing a major leak of unmetered air. I had that happen to me when I replaced my plenum. Had the same problem the second you starte it t was idling at 3000, you clear the codes and it would go to a rough idle at around1000, but the moment you gave it any gas it would go back to 3000rpm idle

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CaddyPete hit the nail on the head. The PVC line was disconnected inside the intake. Took intake loose and connected the PVC line and engine purrs like a kitten...well that may be an exaggeration since it has 167K miles on it, but it runs fine.

Thanks to all who offered help. Greatly appreciated.

Dave

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CaddyPete hit the nail on the head. The PVC line was disconnected inside the intake. Took intake loose and connected the PVC line and engine purrs like a kitten...well that may be an exaggeration since it has 167K miles on it, but it runs fine.

Thanks to all who offered help. Greatly appreciated.

Dave

Great to hear!!! Good feedback too, this kind of info is great for people with future caddy issues. Its nice to find free fixes, aint it?

Jonah

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CaddyPete hit the nail on the head. The PVC line was disconnected inside the intake. Took intake loose and connected the PVC line and engine purrs like a kitten...well that may be an exaggeration since it has 167K miles on it, but it runs fine.

Thanks to all who offered help. Greatly appreciated.

Dave

Great to hear!!! Good feedback too, this kind of info is great for people with future caddy issues. Its nice to find free fixes, aint it?

Absolutely great to have people here who really want to help!!!

Dave

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