P0102 with high idle

Hi guys.

I've hit a roadblock recently with my favorite P0102 code and I'm a bit lost. Hoping that I can get some guidance on this forum. I have found very important info on cleaning the EGR cooler, manifold and other maintenance tips and I'm really grateful for any help that you might provide.



I'll provide a quick history and then let me know if you see anything that I'm missing. By the way, I'm a DYI and not a mechanic.


Prius 2010 with 202000 miles @44MPG

Bought the car with 170,000 miles and I'm not necessarily sure what the previous owner did or did not. My oil changes are done with synthetic oil at 5000 mile intervals.


Here is some history on what I did to the car and the issues that I experienced.

1. Changed my water pump in 10.22 due to code P261B.
2. Changed coolant at the same time
3. Please note that I'm not experiencing any coolant loss whatsoever nor am I burning any oil.
4. Everything was running smooth until mid November
5. During mid November I experienced the famous engine rattle and experienced heavy misfires with cylinder II misfires. I received the usual misfire codes, ignition coil code plus P0102.
6. Thought that I would need a new engine, but I took the following steps to rectify before making that decision: 1. Changed spark plugs obtained by the dealer. Spark plug number two had oil at the bottom of the spark plug. 2. Changed the ignition coils and resolved the misfire issue.
7. Also changed my fuel injectors, and these are aftermarket versus the dealer. Might clean my oem and put them back in but let's see.
8. Car was back at 44MPG

I was not able to resolve code P0102 and gave it some time to see if enough trips would make a difference for the code to clear.

1. Gave up and bought a maf sensor from the dealer but that code never resolved itself so obviously I have other issues.
2. When I changed the MAF sensor, I realized that I never fully tightened the bolts from my EGR pipe that connects to the EGR valve and manifold.
   1. As soon as the pipe was tightened, engine mph increased abouy 30% at idle and my mpg went down for 44 to 41. I cannot recall exactly, but I think I was experiencing high idle before the crazy cylinder misfire.

1. Found the service repair section for maf sensor
2. on the site and the sensor has good resistance, voltage os 11.4v. Almost change the wiring harness, but I don't see any reason to do so just yet.
3. Techstream shows good voltage for the maf sensor on maintenance mode.
4. At this point, I bought a new EGR valve and I'm going to clean the manifold plus the EGR cooler.
5. What has me puzzled is that the car runs better with the EGR pipe being loose however, techstream shows that my EGR valve is open during normal operation as well as during test mode.

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And I missing something other than the EGR cooler or manifold? I'm asking because with the EGR pipe being loose lets more air into the manifold which one would think the EGR valve is stuck closed, but then techstream shows the EGR valve open during normal operations.



Would appreciate any feedback.

Thank you.

 

And yikes, did this on the bus and I see that i made a few grammatical errors.