Hi, everyone!

So, There's 190845 miles on this 2013 Scion iQ and a few months back the check engine came on, as well as the engine running rough that day. I plugged in my OBDII Scanner and the P0302code (Cylinder 2 Misfire). I figured it was in need for a tune-up so I did so, using all genuine Toyota parts (Denso). I replaced all 4 spark plugs, 4 Ignition Coils, Cleaned the M.A.F Sensor, replaced the engine air filter, cleaned the throttle body (Butterfly actuator plate), Replaced upper intake gasket. When I completed all of that I attempted to start the car and the lights came on the dashboard and it cranks but will not start. Also was showing the same DTC Code P0302. This car unfortunately, did sit through the winter up in Tahoe for bit since it hadn't been able to be started. I'm thinking of checking the fuel injector on cylinder 2 next, possibly the PCV Valve and pour some fresh gas in the tank, fingers crossed the fuel filter ?!?. I really hope it isn't the catalytic converter...

Please any DIYers or professionals out there throw some ideas/theories at me!

I appreciate any advice, Thanks everyone!

-Scionlife13

 

Did you reset the ECU after doing all of the maintenance? I know when I touch certain engine parts in my tC it will immediately fire up and die, and then start perfect every other time. Seems like you did all the proper work, reset the ECU (battery unhooked for 30 min or so) and then see if the car will start after. Unless you forgot to plug in the throttle body or one of the other connections there shouldn't be any issues.

 

 

@drizzoh Yes, I reset & erased all DTC Codes and it will not start up. I went step by step to double-check I did not mis any electrical connections.

 

I don't have any ideas but wondering if you got her running again and, if so, the cause of the problems?

 

My check engine light came on and traction control light illuminated as well. The scanner read the same code as yours "misfire". Took it to my mechanic and he diagnosed it as a clogged catalytic converter. He replaced it with a brand new oem part, and the car ran fine afterwards. 2 weeks later, i had 2 accidents due to "Sudden Unintended Acceleration". Now my car is totaled because the car accelerated on two separate occasions and both times the brakes did not work at all. Still trying to find out what happened and who to turn to for help. Already reported this to NHTSA. Waiting on their response.

 

@Engineer_Boo I have yet to get her running again. Got her a new battery and some fresh gas she definitely wants to turn over but there is not start.

 

Hi there. Any update on that acceleration and brake failure reported to NHTSA? That is concerning!

 

was your issue ever resolved? I am also getting a cylinder 2 misfire code with check engine light & TRAC OFF. Will be testing the spark plug in cylinder 2 today.

 

Funny, you say that. Whenever I disconnect the battery on my 2012 iQ for servicing, after reconnecting the battery the first start-up it runs like total ____e, rough idle, stuttering like it is going to die, and then stabilizes after a short drive and second start-up cycle. Pretty much every time every time I disconnect the battery. I was concerned something was wrong but it does this every time, like the system ECU has to refresh itself to regain normal idle and rhythm… so weird.

 

I have also gotten that P302 code as permanent Cylinder 2 misfire. I cleared the codes and haven't had an issue since. Ran some premium fuel in it and it was running well. Just did a spark plug replacement and can tell how much the new plugs (fresh spark gap) improved idle and fuel economy — the original plug gaps were noticeably depleted and way beyond gap spec.