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Scion ia 2016
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Discussion Starter · #1 ·
Hi guys,

since 95k miles i had this kind of problems with shake and misfire in morning start like the other day to go work, now i did change ignition coils and spark plugs, and mpg avg went up from 375 miles to 440 miles everything went smoothly for about 2 days then problem again of shake and misfire came back in morning our long time turned off in the day..is random too some days it happens and some don't shake but still turn on the engine light with misfire code P0303 and P0300 and secondary DTC of U044200 :invalid Data Received from ECM/PCPM "B"

Thanks in any help. Did try today the TECHRON Complete fuel system cleaner in gas tank to see if that help, as i have seen other post with carbon problems..


Thanks!!!
 

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Discussion Starter · #2 ·
Ok, guys update i did Puma energy 93 octane, full tank and today the car has not give the problem of shake the motor, will keep updating tomorrow.

Puma energy is said to work with "cleaning injectors"??

Thanks,
 

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Discussion Starter · #3 ·
well...it happends again..started the car again and it started to misfire and a bit of motor movements then its all stop to move again and normal again..its when starting from a cold start...

thanks any help
 

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Scion ia 2016
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Discussion Starter · #5 ·
P0303 SCION code possible causes
  • Faulty spark plug (s)
  • Faulty ignition coil (s)
  • Clogged or faulty fuel injector (s)
  • Intake air leak
  • Fuel injectors harness is open or shorted
  • Fuel Injectors circuit poor electrical connection
  • Ignition coils harness is open or shorted
  • Ignition coils circuit poor electrical connection
  • Insufficient cylinders compression
  • Incorrect fuel pressure
  • Mass air flow meter
  • Engine coolant temperature sensor
  • Valve clearance
  • Valve timing
  • ECM

soo.....
 

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Have your intake removed and look for Carbon buildup. If you see lots of carbon get in there with a drill and wire attachment. My 2016 has 132k. I had the exact same problem and code at 102k. All the lights turn on and it violently misfires and sometimes different codes come up plus misfire. This direct injection motor needs a GDI specific intake clean every 20k. Manuel says nothing and so did AutoNation. Make sure the GDI specifically used the IV drip feed on a vacuum line. Pep boys has no idea. Brake masters know how to do IV Drip feed of solvent over valves. If not done every 20k it might be to late. Don't let dealer tell you that you need new engine and then try and sell you a car. A good independent shop will know about removing intakes. And proper GDI drip feed. Also mild shacking when the A/C is off could be motor mounts. I had both problems
 

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Scion ia 2016
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Discussion Starter · #7 ·
Have your intake removed and look for Carbon buildup. If you see lots of carbon get in there with a drill and wire attachment. My 2016 has 132k. I had the exact same problem and code at 102k. All the lights turn on and it violently misfires and sometimes different codes come up plus misfire. This direct injection motor needs a GDI specific intake clean every 20k. Manuel says nothing and so did AutoNation. Make sure the GDI specifically used the IV drip feed on a vacuum line. Pep boys has no idea. Brake masters know how to do IV Drip feed of solvent over valves. If not done every 20k it might be to late. Don't let dealer tell you that you need new engine and then try and sell you a car. A good independent shop will know about removing intakes. And proper GDI drip feed. Also mild shacking when the A/C is off could be motor mounts. I had both problems

Thanks man, i was suspecting this as i look all other forums with the "same" problem. But i saw i just need like to rev it a bit soo, for the moment i am using shell prem to try and help for around 2,500(started do in around at 700miles only) miles, then go back to regular, and maybe i pass rev the car on the highway until i reach like 60mph and then switch to automatic....

Been do in that for about 1-2 month and the problem went away...
 

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I think that all motor mounts should be replaced at 100,000 miles as I had to do that with my wife's 2010 Ford Focus. Also, Audi and others have carbon build up and their reason id that people do NOT go full revs. Easy fix- get on the Interstate and keep it floored until you hit the speed limit. Fun AND maintenance.
 

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Does anyone know a good mechanic in the east bay area. My 4 yr old yaris ia just did exact what you have experienced. I tried using crc gdi intake valve cleaner and it was good only for 2 weeks and the misfire became worse right after.
 
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