bad miss & codes

[deadernie]

Developed a bad miss and got code PO304 cyl #4 misfire. But I'm also getting PO171 lean bank 1 (which I'm guessing is drivers side? I know I need new plugs and wires but would the computer lean the drivers side bank if the passengers side was running rich because of the miss? Should the PO171 go away if I fix the miss?

 

[deadernie]

Replaced the number 4 plug and wire but still get the same code for the miss. Can just one terminal on the plug go bad? I did try switching the #4 & #7 wires @ the coil but still got the code for the # 4 miss. Been awake since 9pm last night and trying to fix this since 7am with no luck.

 

[deadernie]

Can the upper intake be removed and replaced without having to replace the intake manifold gasket? I,m guessing my next step is checking the injectors. Any responses would be appreciated.

 

[deadernie]

I was trying to figure out if the number four cyl. Was the one actually causing the miss by unplugging one wire @ a time from the coil and listen to what it sounded like. After the third try my miss turned into a no start at all problem. Now I'm throwing a fit trying to figure out what to do next. Disconnected the battery in an attempt to reset the computer. . . Nothing. Started checking all the fuses. . . . All looks good. Thought (most likely out of desparation) that disconnecting and reconnecting the PCM might do something and it turns out it was barely even plugged in!!! The bolt that is supposed to hold the plug in is sheared off inside the hole and the rest of the bolt is still in the plug but not doing anything. Plugged the 'effin thing back in good and tight and fired right up with no issues at all. Have to get what's left of old bolt out and get a new bolt. Was the last place I would've expected to look for a solution to the problem.

 

[storlied]

Wow.... interesting find. It fixed everything completely?

 

[iwannabamedic]

Cool that get rid of the miss and codes? My 4.0 is doing the same thing

 

[joe doe]

I was trying to figure out if the number four cyl. Was the one actually causing the miss by unplugging one wire @ a time from the coil and listen to what it sounded like. After the third try my miss turned into a no start at all problem. Now I'm throwing a fit trying to figure out what to do next. Disconnected the battery in an attempt to reset the computer. . . Nothing. Started checking all the fuses. . . . All looks good. Thought (most likely out of desparation) that disconnecting and reconnecting the PCM might do something and it turns out it was barely even plugged in!!! The bolt that is supposed to hold the plug in is sheared off inside the hole and the rest of the bolt is still in the plug but not doing anything. Plugged the 'effin thing back in good and tight and fired right up with no issues at all. Have to get what's left of old bolt out and get a new bolt. Was the last place I would've expected to look for a solution to the problem.

makes me wonder about mine now too.
4.0 ohv v-6

 

[deadernie]

Fixed it completely. I don't know much about this ex's history but everything looks pretty original. Still has the original plugs and wires and still had the original shocks. Lol. Don't know what would've caused the bolt to break. I would imagine that somebody had to have messed with it sometime in it's life. Also haven't read about it anywhere. But it could never hurt to check all the important connections for looseness or dirt. I'm sure the extra vibration caused by the miss just accellerated the proble. Working the plug looser until it would not start anymore.

 

[greasemanicure]

If this fixes the same issue with my 96Ex OHV, I will jump for joy. #4 has been throwing codes and has resisted any and all diagnostics, changing plugs, wires, coil, .....
Joe

 

[joe doe]

whre is the computer located?i looked on my passenger side panel and all i see there is the seat belt computer.
mines a 2000 ohv 4.0

 

[deadernie]

whre is the computer located?i looked on my passenger side panel and all i see there is the seat belt computer.
mines a 2000 ohv 4.0

Not sure about yours but mine is under the hood on the passengers side near the top of the firewall. It slides into a slot like a vcr cassette and only the plug is visible.
The plug is about 3 inches wide by one inch tall.