P0300 Random misfires normally caused by vacuum leak and bad fuel fuel-

Answered by rasmataz
68 questions asked

Would that cause it to misfire when it's warm but not when it's cold?

Response from smcgann92562@yahoo.com
1 question asked

I am having the EXACT same issue with my 2002 Prius with 140000 miles. Did you ever find a cause? I had mine in the shop for 3 days and they replaces the o-rings on the fuel injectors because they appeared to be leaking some fuel, but it did not solve the issue. I have cleaned the mass air flow sensor and throdle body. I replaced the plugs last year. The only othe issue with the car is that the A/C only works for a little while and the green light stops flashing and it stops cooling. I assume this is unrelated but thought I would share as much data as possible since this is a tough one to solve.

Thanks

Answered by Spreacker
0 questions asked

As the spark plugs heat up, their resistance increases. That could cause it. It could also be a vacuum leak that doesn't happen until the leaking part heats up and expands. Try running a can of good quality fuel system cleaner through your tank, change the plugs and wires, and check to make sure the coils) is/are functioning properly once heated up.

Answered by rivermikerat (expert)
5,494 answers provided