Jim Grant's Tech Tips
00 Nissan Altima, Reoccurring Computer Fault
I own a 00 Nissan Altima that keeps showing an OBDII code of P0304. Ive installed new plugs, rotor, cap, and fuel filter 4 months ago (60k mile service) and it has been running great until last week. I swapped plugs, cap & wires and resistance is good, timing is dead on, driveability very good plenty of power and doesnt seem to misfire when driving, only intermittently at idle. I listened to the injectors; they're all clicking the same. I performed a visual check of all the vacuum lines and they all look okay. I suspect a vacuum leak (should be random misfire) or dirty injector. Any hints?
- Ron Culpepper
A vacuum leak is possible but youll usually get a system lean code pending or when checking the long and short term fuel trim numbers from the computer youll see enrichment occurring. The injector is a possibility for an idle problem. If you dont have the diagnostic tools to get into the computer and fuel system then try switching the #4 cylinder fuel injector with another cylinders injector. If the computer code moves to that cylinder, you can pretty much bet that there is an injector problem. If the problem remains, you'll have to get to a repair facility that has the correct tools and training to deal with your computer code.