What does code P304 mean?

Asked by Oct 22, 2015 at 03:18 PM about the 2007 Subaru Impreza 2.5 i

Question type: Maintenance & Repair

2 Answers

5

From Google not sure. "A P0304 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #4. A code P0304 may mean that one or more of the following has happened: Faulty spark plug or wire Faulty coil (pack) Faulty oxygen sensor(s) Faulty fuel injector Burned exhaust valve Faulty catalytic converter(s) Running out of fuel Poor compression Defective computer"

4,950

Simple. Your #4 cyllinder misfires/d (all it takes iis a one millisecond error to flag the CL!). #4 is nearest the driver's seat (left rear plug). First check that the wire boot is fully pushed onto its plug (this takes a little effort). Then check the wire plug at the coil end: you'll often find a wire running too closely to the metal coil base and/or the intake manifold. Just twist the boot a few degrees to drape it away from metal. Otherwise it can "spark" intermittently by shorting to ground in wet weather. Lastly, if boots are tight and drraped nicely and PO30X appears again, remove the indicated spark plug and check for old age or a LOT of oil on it from leaky valve cover seals. If old replace all 4 with the new cheaper iridium ones. If wet pull all the plug wires and wipe them; then add a bottle of stop-leak sealer to the oil and wait a few weeks for it to expand the weepy seals and keep the plug(s) from fouling. Also NEVER use 5w oil, as it'll seep through all these seals too easily. Use 10w if you have winters; otherwise 20w50 if in the south. VERY RARELY will an actual ignition cable be intermittent because an idiot wrench pulled on one too hard and separated the inner fiber conductor from the boot's plug metal clip. So if all else fails spend $40 on new wires. Easy peasey.

Your Answer

Add photo

Related Questions

Search Subaru Impreza Questions

Subaru Impreza Experts

#1 TheSubaruGuruBoston
TheSubaruGuruBoston
Reputation 900
#2 F_O_R
F_O_R
Reputation 470
#3 Nick Eidemiller
Nick Eidemiller
Reputation 460
View All

Related Models For Sale

Used Subaru Impreza WRX
63 Great Deals out of 1,357 listings starting at $3,500
Used Subaru Outback
388 Great Deals out of 40,803 listings starting at $1,395
Used Subaru Legacy
235 Great Deals out of 12,588 listings starting at $1,399
Used Subaru Impreza WRX STi
33 Great Deals out of 645 listings starting at $10,125
Used Subaru Forester
410 Great Deals out of 31,675 listings starting at $995
Used Honda Civic
862 Great Deals out of 85,312 listings starting at $500
Used Mazda MAZDA3
386 Great Deals out of 29,694 listings starting at $1,495
Used Honda Accord
1,026 Great Deals out of 68,855 listings starting at $1,000
Used Toyota Corolla
969 Great Deals out of 69,552 listings starting at $1,999
Used Ford Focus
755 Great Deals out of 54,928 listings starting at $1,200
Used Honda CR-V
984 Great Deals out of 57,183 listings starting at $1,000
Used Toyota Camry
1,202 Great Deals out of 84,836 listings starting at $750

Used Cars For Sale

2017 Subaru Impreza For Sale
14 Great Deals out of 13,583 listings starting at $16,915
2016 Subaru Impreza For Sale
45 Great Deals out of 785 listings starting at $13,999
2015 Subaru Impreza For Sale
23 Great Deals out of 695 listings starting at $12,766
2014 Subaru Impreza For Sale
46 Great Deals out of 1,223 listings starting at $8,995
2013 Subaru Impreza For Sale
16 Great Deals out of 615 listings starting at $5,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.