I had codes 20, 26 and 27 (obviously had to do with my OMP, or something in relation). Replaced OMP and only had 27 left. Drove home and pretty much parked. Then a friend and I went through the full diagnostic check and decided it must be the wiring harness. Put the car back together and didn't drive it for a few days. Then had to move it, and being the amateur I am, I flooded the engine. Checked spark plugs and they needed replacement, so I replaced them. Got the car running great, except for a vacuum leak. So tonight, with help, I found the vacuum leak at the MAP sensor and created a temporary makeshift solution. immediately as I remedied this which eliminated the rough idle, the CEL came back on and was reading code 27 again. Now here is my question: What is the most likely culprit to throw 27 which is directly related to the MAP Sensor? Or was this just fluke timing and I need to re-diagnose everything?

 

I think it is a fluke reset everything and go at it agen

 

Did an ecu reset and 27 came back on after 3 blocks of driving.

 

Are you in Limp mode?

 

yup. Back in limp mode.

 

If you cleared all the codes and that one comes back.....
1. You got a bad OMP for replacement
2. There is a continuity issue somewhere between the ECU and pump
3. I think it might be rare, but I suspected something may have caused the OMP to fail on my car...twice. I lost two OMPs in relatively quick succession (~ 9 months) back when I was on the stock ECU. BOTH times it occurred during or immediately following a WOT boost run. I replaced the OMP a third time and moved to a PFC. That one has been working flawlessly since (~ 4 yrs). Could have been two cases of #1 above, but there you go.

 

I'll be checking continuity tonight. I suspect that's what's wrong because the last time I checked it we were getting inconsistent readouts from the multimeter. On the plus side (I'm trying to be an optimist here), we are getting close to not-sports-car-driving-season so I will be able to save my pennies for a new wiring harness(I'm hearing good things about rywire) and then also a PFC.