oSoFast

Symptoms so far:

1. CEL - 301, 302, 303, 304 (always those 4 codes)
2. car hesitates during acceleration(not always, but more than 50% of the time)
3. weird shaking during idle, sounds like it's going stall (not always, but more than 50%)

This problem has been going on now for about a month, and I've been trying to fix it myself. I've tired the following already, but to no avail:

1. compression test
2. leakdown test
3. new OEM spark plugs
4. borrowed another set of coil packs

Spoke with my mechanic and he said it could be the fuel pressure regulator. Any ideas or suggestions would be greatly appreciated. Thank you

chrisesteban

got the same problem.cars sitting in the garage now.

oSoFast

Sorry to hear about that, I saw your thread also. Seems like you are getting random misfire codes, but I'm always get the same 4 codes.

My mechanic doesn't have time to check the car out until Wednesday, so I'll keep you update with my situation.

sunhita

Also possible:

Bad Gas (mixed with water, R/M= <91 octane)
Bad wiring harness

oSoFast

I think it's safe to rule out the gas, since I've been driving the car still and filling up with 91 octane from a few different places.

How would the wiring harness cause this? Thanks

sunhita

check the engine wire harness connection. Sometimes, the plastic plugs cracked, wet (corrosion) which may deliver inconsistent electric current.