2005 Toyota Corolla miss fire on acceleration cant scan obd2

[Liam.N]

so my girlfriends Toyota Corolla Seca 2005 1.8 L Auto started miss firing on her way home from work to the point where she didn't want do drive it home. so i drove it home it was miss firing on acceleration. 

When i looked at it i seen that one of the coils has a crack going though it. So i ordered a full new set of ignition coils from eBay and replaced them when they arrived after a week. when i first drove the car it drove mint no miss fire took it for about 10 minutes then had some dinner and drove home no problems so i thought it was fixed 

when my girlfriend went to take the car the following day it started doing the same miss fire on acceleration and is back to how it was 

since then I've tried 

-cleaning maf

-cleaning cam shaft pos sensor 

-cleaning throttle body 

-alternating all the igntion coils that i have (2 OG Toyota, 1 NGK and 4 Ebay)

-pulled the sparkplugs out they do have a little bit of build up but I replaced them when we got the car 9 months ago

 

and still no luck or improvement it got so bad car wouldn't stay on. Then  I cleaned the maf out and it made it better but it still has a miss fire 

ive then tried to get it scanned at super cheap and they couldn't get it to work 

I then bought a scan tool and it still didn't work :(

so i thought my obd2 plug was broken its getting power and both grounds work i also checked the pins and popped one of them out from the plug to try and tighten it 

the scan tool still wouldn't work. then i found out that in Australia and New Zealand OBD2 wasn't the legal standard until 2006 and this car is a 2005 but why would it have the plug then ??

 

not sure what the problem is im thinking sensor or coils? 

I've been trying to chase why this obd2 isn't working so idk what to do now 

 

Currently I'm draining the ecu in hopes to "reset" it 

 

If anyone else would have some advice or input it would be greatly appreciated <3

[Squalled]

Might be worth getting some new spark plugs to rule them out and also cleaning the O2 sensor. I've seen some people over the years have issues with the eBay coil packs but try and start with the cheaper troubelshooting options before going further.

[Dannyb21]

I have the same problem with my 2005 Corolla Ascent. On cold start up it misfires very noticeably and once warm, it still misfires, just not as loud and in your face. It's worse with the air-con running, but seems to clear out after approx 1600+rpm. There is a very noticeable smell of fuel coming from the exhaust as well. 

I had the same issue with the obd2 reader from Supercheap so I ended up going to a dealership and they plugged in to it perfectly fine using a snap on reader. Did not show up any fault codes whatsoever even though Toyota could see and hear the misfire. They advised to run a bottle of injector cleaner through it to see if that helped, but no good! Not 1 ounce of difference. 

Years ago I had this same issue when I ran 13b rotary injectors in my skyline. The rotary injectors dumped more fuel than a normal injector so it would misfire on idle and initial acceleration until the revs increased and burnt off the unused fuel. I ended up having to set my idle at 1200rpm so it was high enough to burn the fuel being dumped by the injector. 

So it makes me think that maybe there is an injector problem and that they aren't opening and closing properly. I've done the whole cleaning of sensors etc and new plugs, and the best I got was with the new plugs and it helped calm the misfire to a "just noticeable" level, but then as you clock up the km's, it gets worse! 

I have noticed what sounds like an air/vacuum leak coming from somewhere and its just 1 little vac leak/fart sound (if that makes sense) every second or so. It's sort of like it's doing it every time the piston hits TDC?! Even Toyota said that it could very well be a leak causing it because if its sucking in bits of ambient air, that could/would throw the air/fuel mixtures. 

I'll try and take a video of the leak sound as well as the misfire tomorrow so you can compare to yours.