O2 sensor will cause the code but not a misfire...
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Jeep Misfire problem
- Thread starter SMLEshooter
- Start date
Had similar problem with my 95 wrangler. Happened almost every time it rained. Turned out to be moisture getting in distributor cap.
Ya if you havent replaced the cap and rotor then you need to. A distributor cap can build up carbon and cause misfires and throw off your timing but once its begins that, things deteriorate pretty quickly. For something thats been intermitantly re-occuring over 20-30k miles, you've got something else going on. Possibly your coil is weakening or acting up when it gets hot. You can ohm out your coil to check the windings. Could be a bad wire with chaffed insulation allowing an occasional ground.
Just remembered something. We used to put plastic wire loom over all our ignition wires. After having a few vehicles with misfire codes and shorted coils, we started putting it on all our vehicles (private fleet). If an ignition wire rides on a ground source such as a valve cover long enough, the wire insulation breaks down and allows a partial ground. That leaves you with a weak charge going to the spark plug and a not so hot spark. Electronics are weird and the thing that you think would never cause a problem actually could. Also, an ignition wire thats been grounding for a while will have a white dusty substance around that portion of the wire and the object its been grounding on. I dont know what it is but its a by-product of a high voltage short..
MAP or MAF sensor. Try cleaning it (if you can) or replace it.
Its called Corona.
They got a name for everything! Googled it and did a little reading...just another example of how strange electricity is. Now I can get the guys excited when I pop the hood and yell free corona.
Son in law is a mechanic.. he was talking about an auto that another mechanic had worked on and could not fix the issue then the shop brought it to him. He mentioned that the radio had a short and wasn't working.. I said well theres the problem. He kinda looked at me and asked how did I know? I simply told him that everything is connected to the computer now and a short there can cause a fault elsewhere. By the way he had already solved the issue and it was indeed the radio.
Replacing them won't hurt, but it's not going to help. The code only means the signal is beyond what the computer is looking for. The 0301 code is where you need to focus your attention, its a #1 cylinder issue. Check your lines to the tank and charcoal can for the 0455 code and maybe the gas cap, you've got a leak some where. Since you just dropped the tank start there.
Do you have the coil pack instead of plugs and wires and one coil?
Dude I've had so many of these issues with jeeps over the years.
It helps to have codes in the system to give you a genera idea of your issues.
One of the biggest culprits is the damn crankshaft position sensor....it will act up and sporadically misfire and sometimes not leave a code or you will get a code for camshaft and or crankshaft position sensors.
Po301 is cyllinder #1 misfire in which. I always start with a cap, rotor, plugs and wires with every used jeep I purchase for any misfire codes.
Could be a bad injector yes.
Could also be a problem with the distributor or more likely the camshaft Hall effect pickup sensor under the distributor cap.
I've also,had bad ignition coils act up because upon removal I find cracks in the coil where the spark can jump to a ground path....in most cases this is because the crappy engine block to chassis ground strap at the rear of the engine is corroded and not doing much but making the coil heat up due to straining to make the spark jump from that crappy ground.
Solution: add another ground from your negative battery terminal to your engine block.....I connect mine to the a/c bracket bolt.
I also replace ALL of my battery supply cables with a generic but quality set that I mix match from the auto parts store.
Replace that coil if its cracked, fix that ground, get some new battery cables and you may notice a difference.
Probably not a bad idea to replace the crankshaft position sensor.
Cat plugged up?
I've seen 02 sensors cause misfire issues.
Also check your plug connectors at the engine ecu and wiggle them gently with engine running to see if it skips while you manipulate them.
I always get some long zip ties at the homo depot and route them around the ecu and over the harness connectors to keep them snug with a solid connection.
A lot of this is preventative and some is a good fix.
Another thing that can cause your engine to skip at highway speeds is your throttle position sensor....sometimes they throw codes, sometimes they don't but they can and will do that exact jerking thing while driving and is very similar to the issues you get from a bad crankshaft position sensor.....nice to have codes.
You will be thanking yourself if you can obtain genuine mopar parts instead of the junky parts store knock offs.
I get my stuff from world-PAC and they can get me mopar parts cheap.
Dude I've had so many of these issues with jeeps over the years.
It helps to have codes in the system to give you a genera idea of your issues.
One of the biggest culprits is the damn crankshaft position sensor....it will act up and sporadically misfire and sometimes not leave a code or you will get a code for camshaft and or crankshaft position sensors.
Po301 is cyllinder #1 misfire in which. I always start with a cap, rotor, plugs and wires with every used jeep I purchase for any misfire codes.
Could be a bad injector yes.
Could also be a problem with the distributor or more likely the camshaft Hall effect pickup sensor under the distributor cap.
I've also,had bad ignition coils act up because upon removal I find cracks in the coil where the spark can jump to a ground path....in most cases this is because the crappy engine block to chassis ground strap at the rear of the engine is corroded and not doing much but making the coil heat up due to straining to make the spark jump from that crappy ground.
Solution: add another ground from your negative battery terminal to your engine block.....I connect mine to the a/c bracket bolt.
I also replace ALL of my battery supply cables with a generic but quality set that I mix match from the auto parts store.
Replace that coil if its cracked, fix that ground, get some new battery cables and you may notice a difference.
Probably not a bad idea to replace the crankshaft position sensor.
Cat plugged up?
I've seen 02 sensors cause misfire issues.
Also check your plug connectors at the engine ecu and wiggle them gently with engine running to see if it skips while you manipulate them.
I always get some long zip ties at the homo depot and route them around the ecu and over the harness connectors to keep them snug with a solid connection.
A lot of this is preventative and some is a good fix.
Another thing that can cause your engine to skip at highway speeds is your throttle position sensor....sometimes they throw codes, sometimes they don't but they can and will do that exact jerking thing while driving and is very similar to the issues you get from a bad crankshaft position sensor.....nice to have codes.
You will be thanking yourself if you can obtain genuine mopar parts instead of the junky parts store knock offs.
I get my stuff from world-PAC and they can get me mopar parts cheap.
