Misfire on cold idle - but goes away if I rev car for 20 seconds?

odharwood

New member
 Cambridge
Hi all,

I recently bought a e85 n52 2.5i and got a check engine light almost seconds after I left the seller's drive.

After purchasing a Foxwell NT301 fault code reader, I could see that I had a code for P112D.

Having then looked at the live data, I established with reasonable confidence that the issue was due to a pre-cat lambda sensor. I've not yet replaced this.

However, while also doing an oil change, I took the oil cap off (fairly aggressively, admittedly). Ever since, I have had a misfire on cold start.

This misfire is fixed if I lay on the gas in neutral for 30 seconds between 1-2k rpms. After this, the car is fine. Seems odd. Not sure if it's related to the previous P112D error code.

Any ideas as to what this could be would be greatly appreciated.
 
Fairly agressively, what happened, are you sure the cap sealed when you replaced it.

If you have a misfire the scanner should tell you which cylinder, if you have a misfire there will be several codes are you sure your scanner is showing BMW codes correctly
 
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