What could be causing code P1399

I believe it's a multiple misfire code. I'd get it once in a while, but it would go away by itself. At the time of the code, the MIL light would flash for a few seconds then go away. I can see that the code is pending on my reader as pending. The MIL light never goes solid though. What's wrong? I've replaced the spark plugs and checked coil.

Another thing. The only time this happens is during low RPM or idle and with my head lights on.

topgunsnsx said:

I believe it's a multiple misfire code. I'd get it once in a while, but it would go away by itself. At the time of the code, the MIL light would flash for a few seconds then go away. I can see that the code is pending on my reader as pending. The MIL light never goes solid though. What's wrong? I've replaced the spark plugs, air filter, and checked coil.

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clean your egr valve.:wink:

carbon build up.

Ron, can you elaborate on the process? Does it involve removing the EGR valve from the car or just cleaning it while still attached? Any details would be appreciated. Thank you.

RON98 said:

clean your egr valve.:wink:

carbon build up.

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You also may wish to check your alternator belt tension. If the headlights being on at idle cause it, this is a drain on the system. The alternator is quite capable of handling this load, assuming the belt is tight, and it is working properly.

HTH,
LarryB

I have the same problem on a customers car , exactly the same , comes on only at cold start , and sometimes idle .

Let me know if you're able to fix it. Do you think it's causing damage to the engine?

angus said:

I have the same problem on a customers car , exactly the same , comes on only at cold start , and sometimes idle .

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I'm thinking EGR could be leaking ?

EGR problems are rare and the ERG valve position is fed back to the ECU so if its not in the proper position you will get a EGR code.

topgunsnsx said:

Another thing. The only time this happens is during low RPM or idle and with my head lights on.

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How low of an idle? I would try cleaning the throttle body.

I'm not 100% sure but the tiimes that I do get the blinking MIL and momentary lost of power is always when the car is started and driven. It has happened after letting the car sit for a few hours or just a few minutes. Don't ever remember seeing blinking MIL after driving for awhile. I also tested my idle and it appears right below 800 RPM and seems steady with and without everything turned on. Everytime the fan comes on it'll jump a couple hundred RPM, but always goes back to around 800 RPM.

I've already cleaned the EGR valve / tubing and sprayed throttle cleaner into the air intake manifold. Am I not cleaning it correctly?

Briank said:

How low of an idle? I would try cleaning the throttle body.

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Brian, what I mean by low RPM is when I'm driving under 2500 RPM. Not that the idle is low. Idle seems pretty constant around 800 RPM. Sorry for the confusion and thanks for your input.

Briank said:

How low of an idle? I would try cleaning the throttle body.

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I checked the alternator out and it appears okay. Cable tension looks pretty tight.

Larry Bastanza said:

You also may wish to check your alternator belt tension. If the headlights being on at idle cause it, this is a drain on the system. The alternator is quite capable of handling this load, assuming the belt is tight, and it is working properly.

HTH,
LarryB

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Any solution to the p1399 code?