Engine knocks and shakes on acceleration and check engine light flashes,it dies randomly, and loses power when I accelerate. Changed the coil pack and spark plug on cylinder 8 to fix the misfire code, but it still gives the same code.
No engine told at all.
308 really means, this.
#8 combustion pressure (HP) power is weak, or weak combustion.
caused by many things not just spark 3 things ASE otto cycle gas engines.! (basics)
1: bad engine, bad valves and compression test on #8 fails
2: spark bad #8 spark plug, wire set HV or COP bad. to 8 or cop boots bad on #8 (boots HV carbon tracked or useless)
3: injector bad. leaking or 1/2 clogged or even dead.
in that order, other odd cause but real.
intake runner gasket to #8 is sucking air, aka bad intake gaske.
some cars injector 8 has a bad seal ring sucking air.
bad head gasket but near #8 is worse .
warped head #8 worse here. and makes gasket fail overheated engine top cause.
keep in mind all we know is #8 is weak not why, only tests using real tools finds it.
I do a compression test on #8 and below 150psi is no good WOT.
swap injectors 7 <:>8
do RAD leak down test find coolant leaks not discovered yet.
check scan tool PID LTFT on both banks. SAME,
check 02 , S1B1 and S1B2, FOR CLOSED LOOP STATUS HOT IDLE
MAKE SURE HOT ENGINE PID ECT IS 180F SCANNED.
engine unnamed.
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SOURCE: 1999 toyota camry
Take it to autozone and have them to pull a code on it.It sounds like O-2 sincer
SOURCE: Check engine light on
There are three kinds of gasoline engine misfire scenarios, first there is the "under load" misfire and there is the "at engine idle" misfire, and finally there is misfire continuously. All engine misfires exist because one of three things has occurred. First, a cylinder has lost compression, a cylinder needs a certain amount of compression to operate correctly. Second, the ignition system has failed or is failing intermittently, spark is needed at the time of compression to ignite the fuel air mixture. Third, the fuel air mixture is incorrect, proper mixture is needed for the ignition system to ignite fuel properly. If any of these conditions occur in the engine, the engine will misfire.
1. Low or no compression can be caused by
a. burned or leaking intake or exhaust valves
b. worn or broken piston or piston rings
c. worn out camshaft
d. wrong weight motor oil was installed holding the cam followers from adjusting
e. broken valve spring
f. failed head gasket.
2. Ignition system has failed or is failing
a. spark plug has fouled or is worn out
b. ignition coil
has failed
c. spark plug wires have shorted
e. engine control module coil driver has failed
3. Fuel/Air Mixture is incorrect
a. vacuum leak at the intake manifold
b. fuel injector has failed
c. EGR valve is stuck open
d. mass air flow sensor has failed
e. oxygen sensor has failed
f. air intake boot is cracked
common problems:
1. fuel injector has failed or is failing
2. spark plug wire has shorted
3. spark plug is worn out or is cracked
4. ignition coil has failed is failing
Testing a coil on the car is pretty easy. No special tools are required. Just remember to be careful, the amount of electricity generated by your ignition system can be dangerous.
If your coil is already off the car, or if you would like a more specific data-driven test, you can bench test your coil. To set up the test, remove one spark plug wire from its plug, then remove the spark plug using a spark plug socket. Next put the spark plug back into the spark plug wire. Be careful not to let anything drop into the empty spark plug hole -- very bad.
SOURCE: 1998 Dodge Intrepid: engine misfiring
usually wires ign wires & plugs but could be your ignition coil!!test it don"t guys$$ have a spark tester if not invest in one don't bother using a spark plug your just waisting time with that!~
SOURCE: Check engine light
A multi misfire may mean that one or more of the following has happened:
Faulty spark plug or wires, Faulty coil (pack), Faulty oxygen sensor(s), Faulty fuel injector(s), Stuck/blocked EGR valve / passages, Faulty camshaft position sensor, Defective computer.
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 wire, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the 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.
Good luck and hope this information helps, keep me posted, be glad to help you get the truck running 100% again. Not sure if your running a K&N air filter, and if you are there may be a flim of oil on the MAF sensor that is making you run lean. You may want to spray down the MAF sensor with a can of MAF cleaner.
SOURCE: 2004 Neon SXT cylinder misfire
TRY REPLACING THE CRANKSHAFT POSITION SENSOR..HAVE SEEN THESE CAUSE MISFIRES AND LOW VOLTAGE DTCS AS PCM THINKS VEHICLE IS NOT RUNNING..ALTERNATOR MAY NOT BE PUTTING OUT PROPERLY
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