Map Sensor Problems.

[Jackrabbit916]

Hello everyone. I am new on here and I am having a very perplexing problem. My 04 SE keeps telling me that I have a bad map sensor; however, every time I install the new map sensor, the car starts to immediately report multiple random misfires. Code: P0300. It will only stop by my placing the original map sensor back into the car. I have replaced the spark plugs, wires, coil packs, and the pvc all to no avail. I ordered an oem replacement for the sensor as I thought that buying an off brand was causing my problems; however, this turned out not to be the case. I am truly stumped. Any help would be very much appreciated. Thank you in advance.

[harofreak00]

Are you confusing MAP and MAF?

What is your actual code number?

[Jackrabbit916]

No confusion. It's definitely the map sensor and not the mass airflow sensor. If I change the old one out for the new one I throw a P0300 almost immediately. Everyone I've talked to about the issue is just as confused as I am about what the heck is going on. Thank you for responding. It's driving me crazy. As soon I change out the old map sensor with the new one the map sensor problem goes away, and I return to P0300.

[harofreak00]

What is the MAP sensor DTC you are getting?

So the MAP sensor and the MAF sensor work in unison. If either one is not functioning properly it will use the other to determine the fueling tune.

Disconnect the battery and touch the terminals together to clear out any memory in the computer, install the new MAP sensor, but disconnect the MAF sensor. See if it runs any better without the MAF connected. It will still throw a P0102 code because its disconnected, but if it runs better you know you have a bad MAF sensor. These MAF sensors don't always throw codes when they are going bad.

[Jackrabbit916]

Going to give it a try today. I will update you on the results. Thank you for helping me out.

[Jackrabbit916]

Update: So I did try what you suggested, and the misfire went away when I left the MAF sensor unplugged with the new Map sensor in place, so I bought one and replaced it; however, once I placed the new MAF sensor installed along with the new map sensor, the misfire returned. What I think in going on is that I have a vacuum leek someplace because I can hear it. I hear a hissing noise coming from my engine when it is turned on, when I turned it off, I also heard a sound high pitched sound like air escaping or being sucked into something. This last part happened when I the engine was off, and it went on for sometime aftwards.

[harofreak00]

Yes it sounds like you are on the right track. If you have an audible hissing sounds it should be pretty easy to use your ear to find it.

[Jackrabbit916]

I appreciate your help as the situation was driving me bonkers lol.