Bucks and hesitates at random times. Acts like multiple cylinders are missing then runs okay. changed the ignition coil, dist. cap, rotor, and fuel filter but no help. could this be a MAP sensor problem?
Additional headache--the ECM would not talk to my scan tool (An Actron cp9180). The scan tool works fine on other cars. I'm wondering if the ECM is going bad?
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code p0300 refers to random/multiple cylinder/s ---misfire detected=== causes spark plug/s--HT lead/s--injector/s---ignition coil/s--low compression --wiring
Seeing as you have covered all the electrics, now concentrate on the injectors and fuel pressures
If you will do all injectors and the fuel pressure is where it is supposed to be ( pressure test) then you will have covered all bases
Low compression will be in the one cylinder only ans will remain in that cylinder regardless of injector or plug changes
I would leave that to the last resort as if it is random, it may be a loose valve seat insert that moves randomly causing a compression problem
Hi Jason: A Random/Multiple Cylinder Misfire Detected unfortunately doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
A code Random/Multiple Cylinder Misfire Detected may mean that one or more of the following has happened: Faulty spark plugs or wires Faulty coil (pack) Faulty oxygen sensor(s) Faulty fuel injector(s) Burned exhaust valve Faulty catalytic converter(s) Stuck/blocked EGR valve / passages Faulty camshaft position sensor 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.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.
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Pop the heed, see the air box on the very left? On top of that box is the Ignition Control Unit. Little black square w/ winds about 1/2"
That is the problem. Or Your MAF sensor...
I don't know how to chech the Ignition Control Unit with out the proper tester.
But the MAF is located directly below in side the box.
If you POP off the large hose that comes out of the front of the air box. You can see the MAF, spreay it some contact cleaner for electronics not BREAK CLEANER>>>>>>.
OBD II 300 Random/Multiple Cylinder Misfire Detected
When the misfire monitor detects a misfire, it will trigger the check engine light with the specific cylinder number as the last digit in the P030X code. For instance cylinder 1 misfire is P0301, cylinder 2 is P0302 etc. In this case we have either multiple cylinders misfiring, or the computer simply can't determine the specific cylinder, and as such we are left with the P0300 in computer memory.
Fuel injectors, related wiring, sensors and computer issues Running out of gas, or poor fuel quality Evaporative emissions system (EVAP) concerns: fuel vapors leaking into engine Incorrect Fuel Pressure EGR system concerns: leaking EGR valve or restricted ports Base engine concerns: low compression, valve train problems and timing issues Ignition system concerns including, but not limited to: Faulty spark plugs Faulty coil or related wiring Ignition module or related wiring issues Ignition related sensor faults or wiring issues
This is a pretty common problem. I would change your valve cover gaskets. They run around ~ 50 bucks. If they are bad it will leak oil into spark plug well and cause a misfire. Very known on the 740.. Also if tune was not anytime not too long ago id change spark plugs while you at it. Then clear the computer and if you still get misfire on 8 try changing the ignition coil which is right about the cylinder with cylinder ignition coil 5. clear the computer. if you get random misfire and misfire cyclinder 5 after then its your ignition coil. parts store runs around 100 bucks