ok so long story short, i bought the car from a dealer, check engine light comes on after an hour... i guess i cant return it anymore sold as is... so i took it into oriley and i get 8 codes, P0101, P0131, P0107, P0301, P0302, P0303, P0131, P0107, i replaced the MAF sensor already to fix the p0101 but nothing, any ideas, my car stalls when on park.

 

btw it idles just a little rough.

 

P0131 is a faulty top O2 sensor (aka upstream, lower O2 is downstream).

P0107 is the MAP sensor. The one located on the intercooler, top center. There is another on the intake manifold but it has a different trouble code.

The P0301, P0302, P0303 are engine misfire codes. This points to the need for a tune up which includes 2 coils, 2 wires, and 4 spark plugs.

If it were my car I'd give it a full tune up including a new upstream O2 sensor first then erase all the trouble codes. Now drive the car to find out which codes return.

 

Check the IAC. A stuck IAC can cause all of that. A code for a particular sensor does not always mean that that sensor is bad. Misfire codes on the old S40 are rarely wires or coils. I would do the plugs and check for spark before throwing coils and wires at it.

 

Hudini thanks for the reply, im gonna do that, full tune up, replace the 02 sensor and map sensor. hopefully that fixes the issue.


ESt6, thanks bud, i will also look into the iac, this is driving me crazy, good thing its nothing serious!


btw what would happen if i continue driving the car like that? i drive 90 miles a day, i prob wont be able to get the tune up done in a week or so.

 

Maybe lower than normal fuel mileage. Can't hurt it though. As long as it's cooling properly, not knocking, and has oil pressure it should be fine. If the IAC fails outright though it might not start without you feathering the throttle.

Just FYI, one poster here said he fixed a misfire by finding the cracked coil and used epoxy to seal it back up. Now I've not tried this so I'm just repeating what's been written. Notice the 2 coils and wires over the remaining 2 plugs are plastic? These can get hairline cracks allowing the spark to jump to the head instead of going to the plug. If you can find the crack you can repair it. At least I've read about it.

 

so i contacted the dealer, he said he replaced the the spark plugs wires and coils, he also replaced the maf and map sensor before he sold it to me, he said they were old codes.. if he has replaced all that what could be causing the random stalling when on park, could it be the o2 sensor?

 

I'd be suspicious of those comments since the check engine light was off before you drove it. Did you have the codes erased? Once erased the check engine light will go out. If the problems persist the light will return.

When you say random stalling does that mean you cannot keep the engine running when this happens? Or is it a sudden failure like an OFF switch? Does the car always restart immediately?

 

Sounds like he read the codes and threw parts at it instead of actually diagnosing it. Like I said, a code for the MAF doesn't mean the MAF is bad. A code for an O2 sensor doesn't mean an O2 sensor is bad.

 

well sometimes when i place my car in park or neutral my car dies, sometimes if i let it sit there for a couple mins, it idles a bit rough and it dies.. but if i turn on the ignition it comes back up right away.

 

Sounds like the IAC could be the cause as EST suggested. Take it off, clean it well and make sure the piston moves freely. I did so on mine and the gasket remained in tact. A new one will run you about $200.