Hi there, and sorry for the long post. I just installed a JDM engine on a 2012 prius for someone at my church. He is out of town for a few weeks, which is good because I am running into some issues. For background, I have done 4 of these engine swaps in the past few years with no problem. The old engine had a blown head gasket on Cylinder 1 (scoped with a coolant pressure test at the dealer), and a code for the water pump speed being off. My guess is that the pump was having issues and overheated the engine. I got a JDM engine from JDM Orlando (they say 60K miles ), and I could see that it had been sitting for a bit. Corrosion on the aluminum, and some unusual rusty spots. It seemed fine otherwise. I proceeded to install it, using the JDM EGR, intake manifold (checked that the little EGR passageways were free), throttle body, injectors, coils, and most sensors (oil pressure one was busted, so I had to reuse the old one of those and I reused the old MAF). New Denso spark plugs. No, I DID NOT scope the cylinders to check for pressure washing. When I started it up there was a severe knocking. I was not too perturbed as this had happened on the second swap I did, and it just needed to restart a few times for the computers to adjust. After a few restarts the engine was running fine and I took it around the block. I noticed that there was shaking under heavy throttle, and halfway through my drive the CEL came on. I scanned it and got: P0301 (cylinder 1 misfire) P0303 (cylinder 3 misfire) P2195 (02 sensor signal biased/stuck lean bank 1 sensor 1) I reset them and swapped the JDM oxygen sensor for the original one and drove it. CEL stayed off, but when I scanned it I got a pending code for P2195 again. And I could still feel a slight shaking at full throttle. Now when I check I just get P0301. I realize that some of this could be another blown headgasket. However, there is no shaking at startup, so I do not think that is quite right. I used to have a scope, but I broke it recently. If we assume that the O2 sensor is telling the truth, then there is either too little fuel, too much air, or a spark that is failing sometimes. With this logic, some areas to investigate are: Clogged/faulty injectors. This is my most likely thought, especially since things have seemed to get a bit better as I have driven it more. I put a bottle of berrymans in the the gas (1/4 full) to try to clean them that way, but they may need more than that. Faulty coils. These would be easy to switch out with the ones off the old engine, but I have never known one to fail. Maybe first I would put the #1 and #3 into cylinder #2 and #4 to see if the location of the misfires changes? Faulty spark plugs. This seems unlikely as they still had the plastic sleeves on them when they came from Rock Auto. As stated they are the Denso ones. A crack in the intake manifold. Some of the other plenum boxes were busted on the JDM one, so it is not out of the question that the manifold was cracked, though I did not see anything obvious. And I would think this would lend itself to more than just a misfire on two different cylinders. There is an EGR issue. I did not take a look at the cooler condition before I installed the engine, but the connector pipe to the intake looked reasonably clean. Also, restricted flow would cause a rich condition if anything, not a lean condition. I am of course indebted to this community for all the help you have given me over the years, and hope that you will be able to provide some opinions on this. I do have a bootlegged version of techstream, so I can look at live data if that would be helpful. I am just not sure what to look at.
