#1&2 cylinders are reading misfiring,p0301,p0302 on a 2001 jeep grand Cherokee 4.7v8 super rough idle and stalling. Already changed #1&2 sparkplugs and coils still same problem what do I do now

SOURCE: Check engine light comes on. p0171 and p0351 codes found

From Lusty Kid:

I know the economy is bad, but change all of the plugs. Check your PCV Valve hose, 150 rottens them out allowing air to be sucked in, thus all kinds of codes.

Depending on mileage. Dismount the EGR valve and clean passages. If you are really good dismount the throtle position sensor body and clean out passages with Choke Cleaner., dismount where the EGR valves connects to the engine, clean out passages. Also check the hose thats behind this mounting to ensure is not clogged. If clogged clean it out. If not replace it. Is about 1.5 ft. long, connects to the PCV Valve Hose.

When is the last time you change your harness. Can't remember??? Replace it. Good Luck

SOURCE: 2002 Jeep Grand Cherokee Lardo misfiring

You say you changed the cam sensor. A1391 code is a crank sensor on the top of the trans. bell housing.

SOURCE: rough idle stalls at low rpm's

check your transmission fluid,the motor will stall when fluid is low

SOURCE: 2004 Jeep Grand Cherokee. Keeps stalling, engine

P0505 means the whole Idle Control system, not only the IAM. Check all related sensors (i.e. crankshaft sensor). Check with a voltmeter direct at the connector of the IAM if you get any signal. Remove the IAM from the TB, connect him, let someone switch your ignition key to ON. The IAM need to drive in/out for a short time to find the right position. Hold the IAM near a hard part, that they cant drive out completely! If IAM works fine, check the fuel pressure, check and clean your TB ( if not done yet). If that doesn't work, come back again please

Ginko

• 19396 Answers
• Posted on Dec 20, 2010

SOURCE: 2002 Chevy Trailblazer, service engine soon

Hi.

The check engine light, driving problems and smell was in consequence of the misfires. If now the car drives fine, the vacuum leak could have been the cause of the original troubles. As far as I understood now the problem is only when idle.
Ensure that you have replaced the air filter , also double check vacuum and check/clean the air intake duct and sensors (IAT, MAP- see here for removal). Those are factors that can affect and cause misfire during idle. The IAC valve can also cause similar troubles and must be checked.

All the part listed above may cause lean or rich mixture. The problem is not necessarily detected by the O2 sensors in the exhaust and may result in no lean or rich code being stored in ECM.

If mixture and air intake are not responsible, and if the problem does not only occurr when idle, check the high voltage wires from coils to spark plugs (particularly if a code on a particular cylinder comes back). Check timing, valves, EGR and fuel pressure/fuel pump. Try doing an injector cleaning and check injectors (both spray and voltage).