Toyota Corolla e120 1.4 vvti 4zz-fe engine random misfire

[Ilija]

Hello Toyota friends i have problem with my toyota corolla e120 1.4 vvti 4zz-fe engine it is on 150.000 km. and it is converted on lpg for about 11 years. Until now i havent had any major problems but ricently it started to show check engine and if i hold it on rev to about 2300 rpm it flashes blinks check engine. Then it turns it self off for some day and then all over again. On diagnostics it shows P300 01 02 03 04 random misfires and its running litle roughly and uneven and on small revs it hesitates on driving.So far i have changed spark plugs and egnition coils and no better changes. So i vas wondering if someone has any experience with this or any clue what to expect.Maybe some valve or sensor or something? Thanks in advance 

[Ilija]

Hello Toyota friends i have problem with my toyota corolla e120 1.4 vvti 4zz-fe engine it is on 150.000 km. and it is converted on lpg for about 11 years. Until now i havent had any major problems but ricently it started to show check engine and if i hold it on rev to about 2300 rpm it flashes blinks check engine. Then it turns it self off for some day and then all over again. On diagnostics it shows P300 01 02 03 04 random misfires and its running litle roughly and uneven and on small revs it hesitates on driving.So far i have changed spark plugs and egnition coils and no better changes. So i vas wondering if someone has any experience with this or any clue what to expect.Maybe some valve or sensor or something? Thanks in advance

[FROSTYBALLS]

Moved to the Corolla club and merged with previous topic.

[Ilija]

Thanks 

[oldcodger]

Hi,

The thing you have not mentioned is are you getting any actual running problems like a physical misfire ?

If its still running smoothly, then it might suggest a faulty sensor.

The link to this ytube shows a wide range of things that can cause P300, but the extra factor for you is how the LPG affect things  or how to test and check that out ?

https://www.obd-codes.com/p0300

 

[Ilija]

For the past year i noticed small changes in running engine litle roughly idling in the morning strog smell of petroll from the exaust, from the exaust i can hear uneven chuf chuf sound occasionally litle misfire if i step on pedal hard and on small revs until 2000rpm litle hesitation when it passes 2000 rpm its running like a champ but nothing constant and it's frustrating somehow i feel it's different every starting or on cold weather or very hot weather so it's variety of symptoms but the check engine problems started 4...5 months ago. Anyway tomorrow or the next day I'll be leaving the car in the mechanics shop so we will see. I just hope that it won't be needing opening of the engine and something serious like  valves because it's only 150.000 km and its been taking care of like a baby. Otherwise it's not burning oil or smoke from the exaust. Thank you  for the reply and sorry for the bad English i use the spelling from the smartphone. Regards