P0300, then P0302 can’t find the problem.

Here goes: 2004 Roadster Touring, 6 speeds, 75k miles.

Early this summer got a P0300 code but engine runs fine. Clear the code. It came back a few days later, cleared it, came back. So I tackled the work. Changed all plugs for NGK LFR5AIX11, replaced all coil-packs with Hitachi’s, replaced valve covers and PCV. Being there, I replaced both cam sensors and crank sensor with, again, Hitachi’s. Replace the water temperature sensor. Then P0302 started to come on. Switched plugs #2 with plug #6 and Coil-pack #2 with #4. Cleared the code. Came back a few days later. Did a compression test as per FSM directive 1-200 2-185 3-195 4-185 5-200 6-185. I then switched fuel injector #2 with #3. No luck, I’m still getting a P0302. I don’t know where to go from here. The engine runs fine. Bad ECU maybe???

Any thoughts welcome.

 

I would start checking for a wiring fault or poor ground connection. You've fired everything in the parts canon I can think of. Good on you for troubleshooting this far and being so thorough. Normally what you have done would have resolved the issue or at least pointed to the cause.
-Icer

 

Thanks for the good words. I'll check the ground connections and see if I can see anything in the wiring...

 

Seems like you did a lot of work that should have solved the problem..

When you cleared the code did you just use a scan tool?

You could try the unhook the battery for a few hours and reset the computer that way.

If the engine is running fine seems like it could be a little computer glitch

Good luck

 

Yes, I did clear the codes with a scan tool. Good point in disconnecting the battery, I'll try that.