I scanned my Jeep and code #P0302(misfire cyl#2) came up. I changed the plugs, wires , cap and rotor. It Still reads P0302 and runs really rough. The oil light also just started to come on during rough idling.

you forgot factor 3
compression test, actuality its test 1 on old engines
90s is old.
the code means weak combustion
all things that effect that, are to be considered.
compression
spark
fuel

Say it P0302 is set and only it, be best to be clear no?
this monitor just measure piston acceleration.
that is all it does. if too slow. fails.
slow means rate of acceptation is slow. at crank.

Dude you just got ripd hard . He's obviously 1 of those garages that do that to people

code p0302 refers to cylinder 2 misfire detected===causes --engine mechanical fault--wiring---ignition/fuel system---injector--ECT/MAF sensor---ECM
code p0457 refers to evaporative emission system--leak detected (fuel cap loose/off) ==causes --mechanical fault--hose connections---EVAP pressure sensor
Replace faulty items. Use only genuine items as replacement
as non-genuine are not always compatible with the OEM fitted CPU units. This results in the fault codes not cancelling out. If possible you may be able to get the CPU reset to work with the non genuine items you already have.

p 0300 is random misfires and 0302 is no 2 cylinder misfire
most misfires are from dirty injectors rather than plugs
run a quality injector cleaner and see if there is improvement

Most likely the coils. Easiest way to check is swap them with another cylinder, start it, pull the plug wire connecter and if it doesn't change the engine the coil is bad. If it is the injector, then you can check it with an ohm meter. Touch the leads in the injector it should read 11 to 15 ohms. if you need help let me know.
Randy

Misfire 2 Cyl generated DTC P0302 Code - Cylinder #2 Misfire

A P0302 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 #2.

Symptoms may include:
* the engine may be harder to start
* the engine may stumble / stumble, and/or hesitate
* other symptoms may also be present

Causes: A code P0302 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

Possible Solutions: If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Hope helps (remember rated this).

mcdevito75 here, Could be a worn timeing belt, a crankshaft position sensor. Have your local shop check it out.

Trouble code P0043 means: HO2S Heater Control Circuit Low (Bank 1, Sensor 3)Hex code 43 is for a misfire.

DTC 43 indicates a cylinder misfire, but does not specify which cylinder is misfiring. To pinpoint which cylinder is misfiring, you need a scan tool and get the "P" code, as you can see in the chart below. So it is quite possible you're barking up the wrong tree.


If you go to an Autozone they will scan the codes for you, if the CEL is currently on, and tell you the DTCs they find. That will get you closer to the problem.
I'm fairly confident that if you do a complete tune-up, spark plugs, spark plug wires, distributor cap and rotor, that the misfire codes will be taken care of. Be sure you read this, Dodge Ram 1500 Running Rough before replacing the spark plug wires, or if you have already replaced them.

Hope this help (remember comment and rated this)..

hola como puedo saber cual es el problema con mi 96 grancheerokie cada vez que acelero despues de 1500 rpm el motor pierde fuerza y avienta explociones por el throurolbody ya cambie los sparkplugs,cables, rotor, cap y el motor ya esta a tiempo [email protected]

it is your fuel injectors, replace them, and the problem will be solved..