Replaced AOS, getting misfire+codes

have got a 2001 c2 cab tip. Had AOS fail with no warning. Smoking like crazy, drove 3 miles home. Replaced AOS. Now getting irregular miss, especially at low rpm. Purchased durametric, clear codes seemed to drive better. But got a CEL, and engine missing again. posted codes as attachment. Help

Smoking and you drove it home ???? You're on your own

oh, I replaced oxygen sensors with factory, and spark plugs. Thank in advance for any input

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Misfires damaging to converters. These are rich misfires. Thus they are (probably) not due to an air leak. Given you just replaced the AOS I'd have to say my first suggestion would be to put it bluntly you screwed something up. While I would generally offer the opinion you left a vacuum hose disconnected or introduced an intake leak since the misfires are of the rich type this takes away these two possibilities. But something you did could have affected the fuel pressure. A fuel overpressure will result in an overly rich mixture. It could be a coincidence but the MAF could be bad. But the above is too far afield, at least at this juncture. Let me get back on track: Ok we have misfires. Rich misfires. Before you dig too deeply be sure you have the right coils and they are installed correctly. Not only at the plug connector but at where the coil connects to the wiring harness. Be sure you have the right plugs too. Be sure you revisit the engine and inspect each hose for proper connection and for any cracks/splits. Check all electrical connectors. While there are no codes related to VarioCam operation be sure the VarioCam solenoid connections are good. In short check for any collateral damage arising from your AOS work. If you find nothing you might consider disconnecting the MAF at the harness and clearing the codes and seeing if the MAF out of the picture helps. Obviously the MAF plays a major role in engine fueling and if it is delivering nonsense the DME can't fuel the engine properly. With your Durametric you could before you mess with the MAF check the coolant and intake air temps looking for a reading that is far out whack. For instance a real cold reading which could have the DME supplying a too rich mixture. Be aware you are dealing with rich misfires. You want to avoid running the engine any more than you have to to avoid ruining the converters. Also, overly rich fueling can wash oil from the cylinder walls which ain't good. The unburned fuel can dilute the oil too and this ain't good either. Oh, I do recall from my Boxster's first AOS event the engine produced error codes and the CEL was on at various times afterwards. Unfortunately I do not recall the error codes. The SM told me this is not uncommon. I was out of town at the time and gave him permission to drive the car. He told me that with driving the error codes go away. I guess the idea is the driving burns away the oiling the engine/sensors/converters were subjected to from the failing AOS, which in my car's case was bad. At the end oil was dripping from the exhaust. When I returned and picked up the car the error code situation while better was still present. With no time to deal with this I put the car on a trailer and hauled it to CA and my new job. When I had time to deal with this what I found after some time was a bad O2 sensor. I'm sure at this point there were no misfire codes. The remaining error code while I do not recall it I do recall it clearly pointed to a sensor. My delay in replacing the sensor arose from me wanting to observe the sensor acting up. I finally was able to see this but it took time. Then I had the sensor replaced and the error code was gone.

The codes all point to intake leak. Was the intake sealed and tight? Alo, any vacuum lines broken or disconnected? What are the readings of all four O2 sensors?

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Unfortunately my error code references are at the office and I'm not and my other references here do not really provide any details. Thus I focused on the misfire codes. But you could be right. Actually, I prefer the source of the errors to be an air leak. I prefer an air leak as this is the most common problem to arise after a, to put it kindly, a botched AOS job.

Quotes source post: 10493536

Yea, all the codes are lean codes on BOTH banks, meaning the DME has maxed out on fuel enrichment. Further, the codes point to same situation at both idle and at load. Without more info, I would also question if the O2 sensors are the correct ones for the car.

I'll check for air leak. Big hands in little areas sometimes don't mix. It's a cab and also a tip, so very little room. Thanks for the insight.

if anyone is still following thread. Oxygen sensors installed are Bosch #13564 pre cat, Bosch 13723 post cat.

After my AOS was replaced, I had the same problem . The MAF sensor was removed and cleaned, and that fixed the problem. This was done twice, once when the AOS was replaced, and about a week later when it started to idle irregularly and I got a CEL.

Did you clean up as much oil in the intake/plenum/manifolds as you could during the repair. There was a surprising amount of amount just sitting in the intake tract during my repair. If that's being pulled into your combustion chambers you will certainly get misfires until it's all clear out. Although this would cause a tremendous amount of smoke...so you'd definitely notice. Otherwise, I'm with others. I'd check the MAF/plenum for air leaks. It's easy to misalign the rubber connectors on the plenum with the left and right manifold.