I have a 2006 Crossfire 6spd. At random and getting more and more often the car will stall or buck forward. The stalling is only in neutral or clutch in, so I think the bucking is just the wheels keeping the engine spinning.

I've got 3 trouble codes showing.
P0442 for an evap leak that I think is unrelated as it's been there for a while.
P0104 for the MAF sensor. I've had issues with this in the past.
P0221 for the throttle position sensor. This one's new to me and from the research I've done seems like a potentially likely candidate.

If it is the TPS then what I'm looking for is whether it's the sensor on the pedal or the throttle body and where to get either one of them. They seem to be unavailable everywhere I've looked.

Thanks for any help.

 

If you are looking through Chrysler almost everything is NLA. If you look through Mercedes as a 2004 SLK320 almost everything is available. If you look on eBay you can find most parts.

 

P0442 is an EVAP code. The Evap system is there to assure you are not venting vapors from the gas tank into the atmosphere because that would kill us all. But it wont make the engine run badly.
P0104 indicates that the ECU is losing contact with the MAF sensor. This can be a connector issue but is more likely due to a bad MAF sensor. Some have had success cleaning the MAF but I'd not bother, I'd replace it.
P0221 is a bad one to get, because MB does not tell us if it refers to the position sensor in the accelerator foot pedal or the position sensor in the throttle body. If you read a LOT about the P022x codes and P012x codes, you will find evidence that:

P022x codes are indicating the Throttle Body is the issue
P012x codes are indicating the Accelerator pedal is the issue

Why the HELL MB didn't make it clear which sensor they are talking about, I do not know. But if you just do enough reading online about these two families of MB codes, Im sure you will come to the same conclusion.
I lean towards a TB issue, but fact is, failures in the accelerator pedal sensor are way more common. Now a bad accelerator pedal will not make the car run rough, but a bad MAF will and a bad throttle body REALLY will screw things up.

I like German Auto Supply, Autohaus Arizona and FCPEuro for parts. I'd search for the Crossfire part as well as the 2003 SLK320 Mercedes part, and buy the Bosch part that is cheaper - they are both the same part but often the one that "fits" the SLK320 is cheaper.

When we ran into a car that would not idle or run right at a tech day about five years ago, we swapped MAF and TB from car to car and found that what ever car had a particular TB on it, it would run badly. One of us ran home and grabbed a spare he had at home. Kinda hard for you to do that with only one car, not sure how you advise you here.

 

OK, I did some more reading late into the night. Found two guys on MB forums that insist that P012x codes are the sensor at the pedal.

Now, you are getting a MAF code And a P022x code (which is apparently the throttle body). I find it interesting that BOTH the MAF and TB are throwing codes. I also think back to the two cars I know of that ran rough, both were caused by TB issues.
I know that pedal sensors fail a lot, but I"m thinking that would cause an unresponsive pedal, but why would it cause the engine to run rough? The ECU/MAF/TB are what run the engine's fuel/air mixture, adjusting for load, speed and pedal position.

I tend to lean more and more to MAF and TB for the cause here. Sure wish I was local so we could swap parts between cars, cause that would be the cheaper way to drill down on this one.

 

The MAF powers right out of the RCM. If the OP has a spare RCM I would swap them and see if that may help. Also the Evap leak may be feeding into this problem as vacuum leaks will indeed cause bad idle.
Check the air intake for no obstructions and clean filters: inspect the throttle body for cleanliness before ordering any parts. I would also check the area near the accelerator peddle to be certain nothing is binding the peddle in any way. Likely cause is the throttle body, but certainly checking these items are important.

 

Yea, I overlooked that, the hose to the purge solenoid/valve would be suspect in this case. If it is leaking, then you have a vacum leak.

But one way to verify a vacum leak is this:
With engine idling, yank off the oil filler cap. If the engine sputters and runs WORSE, you have no substantial vacum leak.

If putting the cap makes NO difference, you have a hell of a vacum leak.

 

We may be wasting our time. He' has not seen any reply but the first one, he came here looking for help and I guess we didn't respond fast enough.
He's not been back since.yesterday afternoon.