Hi, first time poster. I just recently purchased a 2000 S40 with 108k on it. It had codes P1446 P0037 P0505 P0245 P0031 P0130 and P0445. It would start after 10-15 revolutions and run rough. It would stall if I didn't keep my foot on the gas. My reader said to change the PCV valve. I did that job and nothing changed. I checked for vacuum leaks and I absolutely cannot find any. I tried changing the IAC valve and MAF sensor. Now I have a MAF code. So I put the old one back and I still have that code. So I thought that it had to do with the purge valve because of the P0445 code. So I checked that I found that it wasn't sealing. I replaced that, but no change. So I checked the plug and I'm only getting 3.4V on the power side. So I did my own power setup to see if the low voltage was the problem. I hooked the power side to the battery and the ground side to the wire going to the ECM and the idle evened right out. No problems at all. So I go to clear the codes, shut off the car, clear them, and start it up again. It took a second to catch, but nothing like before. And the check engine light stayed off for maybe 5 seconds and then it started running rough again. I went out to check that my wires were still connected. They were fine. I go and check the codes again, and now it's all the same codes, just except for the P0445 code! But I can disconnect the wires, then reconnect them and it seems to completely smooth out. What am I missing? Any help is appreciated.

 

I found that the power going to the IAC is also low, about 2.0V. Is their wiring connected? And if it is, what else is in that circuit? So I can check that too.

 

Long cranking is a symptom of a bad fuel pressure regulator.

I have no suggestions with the wiring or voltages.

 

I took a fuel pressure regulator out of a V40 that I knew was good in and it changed nothing.

 

+1 for the fuel pressure regulator.