I have 2013 prius plug in with 125,000 I had a engine misfire P0304. Compression and leak down was good. Put new spark plugs in and a new coil in cylinder 4. Still had the misfire and cold start up shaking. Cleaned the intake manifold and put in a new egr with cooler. I have no codes, no cold start up shaking ,and no misfire. The whole engine like shakes when you press on the gas pedal for a little bit after it shuts down from warm up. When you are driving the car runs fine when you pushing hard on the pedal, But when you press very lightly the engine feels like it has a slight miss. I am not using any oil or coolant.
Try cleaning the MAF sensor. It may not help, but it is easy to do, and it will not hurt. Posted via the PriusChat mobile app.
When you get a specific cylinder misfire code, a good trick is to swap coils and plugs around, see if the misfire code follows, or not. If not, could be head gasket. Your cleaning efforts are good, but might be too late. Is the engine coolant level stable in the reservoir?
Keep driving until the damage is further It's already started and pretty much done I don't know if you're trying to save something or what's happening more than likely saving is not the issue at this point getting ready to get everything in place for the remedy or getting out of the car or the next points of interest probably
I did swap coils around. Leak down test was 12 %. I am not losing any coolant. I cannot see that I have bad head gasket problem. So I am not going to change it. I do not have any codes now. The problem is minor, I just wanted to know if anyone else had experienced it. I put new plugs in and maybe one is not right.
Yes you need to track down if you have a miss or do you have a stumble Is the fire being put out or is the fire not in proper control.
Another thing that you can try is some Techron fuel system cleaner, add it to a full tank of gas and see if it helps. I like bisco's idea of throttle body cleaning. If it has not been cleaned before, it is definitely due by 125k miles. If you clean the throttle body, you should disconnect the 12v battery for a few minutes so that the car can re-calibrate for the clean throttle body.
The new coil was OEM, I did clean the throttle body and the MAF and MAP sensors. I have been putting seafoam in the tank. I don't think that the engine is missing. The vibration seems like when the HV kicks in.
I used OEM spark Plugs, Now I have P0304 again. Do you think that I have a bad spark plug or bad fuel injector ?
I had the exact same problem you had with a misfire on cylinder 1 instead of 4. I tried to do a coil swap but it still showed a misfire on 1. I also did a spark plug swap but same issue. I did a block test as well and the liquid was still blue. I ended up replacing all the spark plugs with OEM ones and it stopped shaking. The misfire error code went away after a week or so. So after I thought it was fine, I noticed my oil getting slightly murky. I thought it was coolant leakage but my coolant loss seemed fine. I got an oil change and ALL of the oil turned out murky. They told me it was an engine problem but couldn't tell me what exactly. At the moment, I'm debating whether or not I should try to get it serviced from the used dealership I bought it from or just a rebuilt engine from HybridPit. I haven't asked about the cost of the engine + labor but I'm dreading it.
