Imperialblue08

So I had posted about my car having a cylinder 3 misfire. Well I've done a whole mess of work and this rabbit hole just gets weirder and weirder. So I'll start from the beginning. Bought the car at the end of may. Drove it home like an hour and for the next 3 days with bo issues. Cel came on on the 4th day for a misfire. Changed plugs, moved coils and no change. Changed both map sensors since the car is GMS1. Checked the wires like everyone suggested and everything read perfectly. After that cleared codes and came back still saying it's missing on 3. Took car to the dealer for the top engine cleaner as per the TSB. Dealer got the light out but said injectors 3 and 4 looked off but were still in spec. Car drove fine for a week and then came back with the cel. Cleared the light and did a compression test which came back good also. Drove another week with no light then it came back. After that I changed the injectors, intake manifold and throttle body assembly. Drove another week and the CEL came back. Had a code for the camshaft position actuator control valve. Replaced it and that went out. Then it set for a MAF code. Tried 2 new MAF sensors and neither would work. Only the one I pulled out would read. Then I got the light out for a day or 2 and it was back on. This time for a MAP sensor. I cleaned both and no light right now. Personally I feel like my PCM is acting up because anytime the car throws a light ot keeps running perfectly. I can build boost, it idles fine and gets good fuel mileage. Anybody able to point me in another direction or can give me more insight? Cuz I'm about to order a PCM at this point.

ECaulk

iTrader: (6)

Which maf code did you get?

Imperialblue08

P0106. Checked it on my scanner and with the key on and engine off the barometric pressure sensor and that should read exactly the same. I unplugged the sensor, cleaned it and hooked it back up and it started reading the same as the BARO sensor.

ECaulk

iTrader: (6)

Which o-rings do you have on the map/tmap sensor?

It might be worth chasing some wires to make sure there aren't any breaks or worn spots, the car is 10-12years old so those types of issues start coming up.

Imperialblue08

Both sensors I just replaced and changed the o rings with new ones from CED for those sensors. I had checked the wires for breaks and volt tested them and had all the reference voltages and such that were needed.

tomj77

iTrader: (2)

I didnt see that you tried changing the spark plug, did you try changing the spark plug?

bahoodle

if you have 3 bar map sensors that are plugged in with that shitty adapter harness you need to cut the input side off and splice it directly to the map sensor.... mine was brand new n i had to do that for a p0108. that was for the top sensor im assuming yours is for the bottom sensor. i made a post about it a year ago lol

bahoodle

to make sure about that tho check for continuity from pin to pin on the input and output of the wire adapter at the pins.. or take a chance n splice it, whatever your feeling. lol

califcarm

I had some varoius and weird codes popping up for about two weeks that finally settled in to a consistent maf code (p010X, can't remember which one exactly, but means no maf signal).

After already throwinf a new maf on during all the weird codes, I though I better ohn out the wires. Turns out the signal wire for the maf was not making it back to the ecu (yellow wire I am pretty sure that is, but check the elextrical diagrams to be sure).


There is a TSB for strained maf harness near the sensor so I went back about 8 inches from the maf connector and scraped back the insulation so I could check from there to the pin on the sensor. Sure enough it was bad. From that same spot to the ecu did have a connection.

So felt along the wire and could actually feel a spot just about 1 inch away from the connector that was necked down. I scraped insulation away to find the conductor strands pulled apart and broken. I cut back and spliced (soldered) in some fresh wire and all problems went away.

With a tsb for this it is worth checming wiring there near the connector. The harness looks fine from the outside but the wires get pulled inside it, as the harness was really designed too short.

And before it broke cometely the poor connection was throwing codes for map, maf, and evep for weeks leading up to this.

Cobalt4209

might be a bad ground or a short in your harness , could also be a bad ecu ...