2011 Prius P0303 misfire

Good afternoon rtstrider, did you ever solve your issues?

2010 III here w/271K miles now. The engine uses 1 qt of oil every 1,000 miles or so. I had trouble in November with the dreaded EGR valve code P0401. Ignored it. Got ready for a trip to GA from here in NY and severe missing and P0303 appeared. Had spark plugs replaced @ dealer (which had been the originals) and Voila! issue fixed. 5,000 miles later no miss to speak of.
In April I decided to tackle the EGR issue as my annual state inspection was due in May and found out that there was an extended EGR warranty w/unlimited mileage that expired March 31, 2017. Then called Toyota and they basically said, "tough"
I Replaced the EGR valve using a local non Toyota mechanic. He found the EGR cooler was caked w/ crud and spent extra time cleaning it. The miss returned with a vengeance. It happens when the engine is warm.
The first seven minutes from a cold start are heaven, then ugh!
P0303 code had returned.
The local mechanic showed me the spark plug and it was the dirtiest nastiest plug I ever saw. Replaced plugs again after only 30K miles or so. No relief from miss. He switched coils and P0303 continued to return. He checked valves and did some sort of carbon cleaning and missing mostly stopped. He wanted me to drive 30 miles before giving me a new inspection sticker. After 50 miles still no codes. Got my new inspection sticker. Yeah! Drove to my sons house in PA and after 100 mile miles . . . check engine light back on. Another ugh! My indicated MPG after returning home was 51.2 using conservative driving. 55 or higher was normal for me in the summer originally and has been drifting lower.
Missing getting worse. Now P0303, P0335, P0420. Mechanic switched injector 3 w/2 and misfire did NOT follow along to cylinder #2. Reset the codes. 25 miles later no codes yet.

If I push power mode the car misses less.

If I pulse drive e.g. if speed posted @ 45 I accelerate fairly briskly to 52 ish and go back to electric mode letting speed drop to 42 or so then repeat the missing is minimal.

Problem is especially noticeable on transitions between electric mode and gas and viced versa.

Aggressive acceleration and up hill sections eliminate the miss.

Contemplating next step.

More later.

John

 

Oh, by the way I rented a 2017 Ford Fusion Hybrid while mine was in the shop. Drove to GA and back with 49.5 MPG on display. Had bumped tire pressure to 40 all the way round and kept most of the driving @ 65 or lower. Very nice ride even compared to a 2018 Prime that I tested. Quieter, great handling and comfortable yet a little snug in the front seat.

 

Well not many options left here.

1. Replace engine with one that has less miles and clean EGR system.
2. Buy a new Ford Fusion.

Any other option will just empty your wallet a little at a time.

 

272,009 miles. now. using PWR mode. Hybrid battery now stays @ perceptively higher levels of charge. Reach full charge more often and rarely down to 3 bars. Plenty of hills here. Used Chevron fuel treatment for last tankful and will now use Lucas fuel treatment (3 oz/10 Gallons) for next 8 tankfuls or so. Less missing w/PWR mode. Avoiding cruise control helps. Seems a bit better overall. Avoiding gradual transitions especially in low power/acceleration demand situations. Drive routes that avoid low speed stop and start. Driving uphill seems normal.
Check engine light comes on every day or two. Then goes off within 1 day. OBD II ordered. Will watch codes and missing more closely when that arrives. Guessing Auto Zone is tired of seeing me. And expensive to stop @ mechanic for a daily readout.
Drove a 200 mile round trip yesterday and return today. All was fine.
Was hoping for 500 K. Seeming unlikely these days. Taking 1 day @ a time.
MPG remains around 50 w/ conservative driving techniques down from around 55 when new. Would like to get a Prime . . . not this year. Also rear headroom in the Prime/Gen 4 an issue for taller people. A step back in the rear sear to Gen 2 imho.
More later.

John - around 804,000 total hybrid miles. 2001 gen1 345,195,miles. 2004 V, 2010 II, 2010 III and a few rentals over the years.

 

I think the fuel pump is something that commonly starts to go at your mileage

Pixel XL ?

 

The fuel pump on my '01 Prius went @ 288,000 miles. Thanks for the reminder. Now 276,000 miles

 

I’m the same problem on my 21 prius and jus want to ask if you where able to fix the problem, thanks for any info you may give me thanks!!!

 

was the problem solved?