Hey guys, I searched the forum for advice but didn't see anyone talk about this issue...

My discovery is throwing a P0307 with a fairly regular frequency ONLY when the SAI runs. I can shut the car down when the check engine light comes on, clear the code with my Bluetooth obd2 tool, start it back up and be on my merry way. No issues when its warm what so ever.

I pulled the plugs for cyl 7 and cyl 8 and they looked identical, I swapped them as a test and the code didn't follow. I replaced the plugs and wires about 3-4 months ago.

 

strange. The SAI system injects the extra air to inboard exhaust ports. You could disable a solenoid valve for testing on that side (likely will throw a different code).

 

Who's plugs and wires are you using?
I agree with Buzz, SAI should not have any effect of a cylinder throwing a mis-fire.

 

I'm having a similar problem that started last monday. I get the P0307 code ONLY when SAI is running. I was assuming it was down to a bad tank of gas. I'm going to take a look this weekend to see if i can troubleshoot whats going on.

 

I'm running Bosch plugs and NGK wires. Its not the wires or plugs. I agree that in theory SAI shouldn't cause a misfire code, but that is what is happening. Its been a week and 400 miles and it only happens when the sai pump is on.

I can shut the vehicle off and start it up 20 seconds later and its fine (the sai pump doesn't run the second go around). I can park and go in a store or to eat and as long as the pump doesn't turn on when I start no code.

The only thing I can think of is that solenoid is acting wonky, is there a way to clean it?

 

Update: I swapped the sai valves to see if it made a difference, it didn't. After some pondering I've narrowed down the issue to a leaky fuel injector. I ordered a set of 8 remanufactured ones off eBay. The part # is 0280155705 for those that are interested. Total was $140. When I get them installed I'll let you guys know how they worked out.

 

While doing that check your fuel pump pressure at the test port under the intake.

Would think if leak down, turning ignition key to position 2 (pump runs 2 seconds) then off, then repeat several times, then finally crank - this might allow fuel pressure to build up to normal in the system and confirm your leak down idea.

 

This is not a fuel related issue, stop that order if you can cause it won't fix this problem.

 

Then what will Mike? To just say "that won't fix it" with out giving actual input is somewhat silly.

 

How about try unplug the pump or valves and see if problem repeats. It can throw a code for the SAI system, but at least that would not be a misfire. Crushed wiring harness? It is pretty unusual to have such a linkage.