Codes P0068 and P0121

PETERSENROGER02

MEMBER
2004 DODGE INTREPID
2.7L
V6
165,000 MILES

So I need help I don't know what to do to figure this out any further. I know a little when it comes to cars but I try to stay away from shops if I can do things myself, they are just too expensive. I have changed the map sensor and TPS sensor it has been running good, but I've had a engine code on for about a month and a half saying small EVAP leak. So I thought it was no big deal. The other morning I went to start it and it wasn't even drivable. I am posting a video of what it was doing I let it run for a minute or so like this to try and look things over to see what the deal was. I really wasn't sure so I turned it off went back inside Googled some things went back out and started it up and it was completely fine. What the heck? Can anyone please help and tell me how this is and what it is I'd really appreciate it?

I had two codes come up when it started doing that weird deal in the videos I uploaded.

p0068 map/MAF throttle position correlation

p0121 throttle/pedal position correlation/switch A circuit range / performance

It also slightly pauses kind of weird on the take off now only when I stop and give it gas to go again just a little mild pause if that makes sense.
FYI; in the video with the dash in it I tried revving the car up like 2 or 3 times just thought I would add that so it doesn't throw anyone off. Hopefully someone can give me some answers. Thanks

Videos (Click to make bigger)

3 Replies

JONNYB1963

MECHANIC
252 POSTS

Hi,

Can you give me the DTC code for the small evap leak?

I have a theory but wanted to see that first.

Basically the Engine Controller monitors everything related to the health and running of the engine. What seems to be going on here (at least from what I see here) is that the MAP Sensor is not reading what the Engine controller expects to see when the Throttle is in any position.

These controllers are calibrated in such a way where they have tables where the program can look up the information the need for many sets of conditions. In this case, the TPS shows the ECU a value based on its position, the MAP shows the ECU a value representing how much air is flowing into the engine, and the ECU cannot find a correlating value in the look-up table so its getting confused on how to fuel the engine.

Since you mentioned the EVAP leak, it is quite possible that an air leak in the intake plumbing somewhere could cause enough air to bypass the MAP in such a way that it is not reading enough airflow to satisfy what the TPS is calling for. Hence they are not "correlated".

Let me know what that EVAP code is and we can go from there.
Regards
Jon

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Thursday, November 21st, 2019 AT 10:56 AM

PETERSENROGER02

MEMBER
7 POSTS

Well I tried to follow u and make sense of what u said and some of it does. It's just a little out of my league. I only knowledge I have are from the years of working on all my own beaters. Either way the code was
P0442 evaporative emission system leak detected (small leak). Now I did erase that code some time back and haven't had it pop up since all these things have happened or have happened over the last say month or two that was the second time it did that surging in the video I posted it happened twice in about a 2 month span. And both times just stopped after I shut it off for few minutes and started it back up. Except the second Time it did it and went away it left me with that pause or miss or misfire but only on the take off like I explained. Now someone suggested to take my throttle bore out and clean it now I did that today and that miss is now gone I drove it all day and it should have done it do u think any of these things could have been just the throttle bore being dirty? It wasn't terrible but there was black gunk on there. I haven't had any codes pop up or anything again since I erased them two days ago. But that is where I'm at with everything please let me know if u can give me any further advice. I hope this can give u better idea and thank you for your time and help I appreciate it.

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Thursday, November 21st, 2019 AT 7:12 PM

JONNYB1963

MECHANIC
252 POSTS

Okay, That code is definitely a "Small Leak" Generally when I see that, its related to the fuel cap not being tightened properly or the vent in the cap isn't working properly. So in this case its not biggie and not related to whats going on.

It sounds to me like you are on the right track with the cleaning of your Throttle Body. But as an added measure I would also clean the MAF sensor in the same way. They make special spray cleaners for those items. Its amazing what a little gunk can do in the wrong places!

So Go ahead and clean that MAF sensor and monitor the situation for a couple of days and let me know how its working.

Regards
Jon

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Friday, November 22nd, 2019 AT 5:50 AM