whats up guys, its been a while but heres another problem

ive got a cel on today for a p0301 cylinder 1 misfire, from hat ive searched everyone says to do a minor tuneup (cap,rotor,plugs,wires) those have been replaced with all honda parts, i then removed the 40 amp back fuse under the hood and light stays off if i start the car right away, but if i leave the car for over a hr later problem remains and light turns back on...

the car starts and sounds fine, even drives fine still, but i was just wondering if anyone have any thoughts on what else it might be? and what actually causes misfires? so i can get a better understanding to know where to look towards instead of throwing cash left and right trying to figure out the prob. thanks!

 

while you were poking around under the hood, did you happen to notice if this car has 6 cylinders or 4 cylinders?

 

Concidering I don't recall ever seeing an SE V6 I would guess it's an L4. I would say to check the valve clearance if your positive the ignition parts are installed correctally.
A multitude of things can cause a misfire code anything from bad ignition parts, low compression, inpropper valve clearance, and on and on.
It seems like you may have just replaced those things, be sure you don't have a cracked spark plug.

 

Straight from Honda Service News

"When troubleshooting misfire DTCs (P0301 thru
P0306) with the PGM Tester, look at the freeze
data values for the throttle position (TP) sensor
and the exhaust gas recirculation valve lift sensor
(EGR VLS).
If the EGR VLS value is more than 1.25 volts, and
the TP sensor value is 0.5 volt (closed throttle), the
EGR valve opened when it should have been
closed, and is defective. Replace the EGR valve.
If the TP sensor value is more than 0.5 volt, and
the vehicle speed sensor (VSS) and RPM values
indicate that the DTC was set while the vehicle
was moving, write down or print out the EGR VLS
value. Then, drive the vehicle at the same VSS and
RPM as shown in the freeze data, and note the
EGR VLS value:
• If the freeze data EGR VLS value is more than
1.25 volts, but the EGR VLS value from the test
drive is less than 1.25 volts, the EGR valve was
stuck open, and is defective. Replace the EGR
valve.
• If the EGR VLS value from the test drive is
similar to the EGR VLS value on the freeze
data, the EGR valve is OK and isn’t the cause
of your misfire DTC problem. Look for other
possible causes."

If that's no help just stick with what I told you earlier.

 

Are we talking about P0103 (Mass or Volume Air Circuit high input) or
P0301 (Cylinder #1 missfire detected)?

P0301 could be caused by in intake manifold or related vacuum hose vacuum leak.

P

 

Good explanation: This one of those occasions where two contributors post at almost the same moment.

Great post

P