cb11

Last week I was pulling a trailer of trash and construction debris off to the dump and felt a pulsing/vibration and the service engine light came on. Light went off once I restarted the truck so I didn't think much of it. This morning it happened again so I got my shop mechanic to run the code and it came up P0300, multiple cylinder failure I think he said.

Anybody got any ideas that would cause this? I'm gonna go ahead and do a full tune-up but wanted to know if there is something specific I should look for.

Thx. <!--POLLS--><!--FILES--><!--SIGNATURE-->

in2pro

From OBD codes...

Causes
A code P0300 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.

cb11

Thx for the detailed response. That gives me a good idea of what to check. I'm thinking the intake gasket may be leaking, seems like a common problem on the Vortec 5.7's and that would lead to the lean condition you referred to.

Cav1998

1998 chev cavalier 4 door automatic 2.2l OHV Basic car. I had a check engine light so my expensive OBD 2 code reader gave me the code P0300, ( random misfire ). I am Googling eveything all forums say things like pcm, icm, coil pacs, spark plugs, spark plug wires, wiring harnesses, etc. Problem was not any of these so, here is a history. 2 daughters used the car as loaners, Daughter #2 used and the original Engine #1 72,000 miles blew a head gasket so I replaced it. Daughter #1 used it and blew #2 cylinder piston 162,000 miles and the tranny went out. Replaced engine #2 and automatic tranny. It now has engine #3 185,000 miles and tranny #2 20,000 miles later Daughter #1 bings it back to me 1 year later with tranny slipping and the check engine light. Original starter, alternator, icm, coil pacs, pcm. When checking under the hood I can hear a hum out of the alternator. Alternator is removed and checked out at a parts store and it passes but, I do not trust it. Sounds like a parasitic electrial leak from the altenator diodes. I buy a new alternator and the hum is gone. The alternator has 3 wires going to the pcm. I think the parasitic leak was messing with the spark. The battery was replaced at the last engine change. When I replaced the alternator I had to replace the Battery also, it would not hold a charge and there was no warning light for the battery illuminating. I drive the car at highway speeds for a week and no more problems, and no tranny slipping. What she thought was a tranny slipping was the random misfires ( P0300 code ) causing loss of power out of the motor. No more check engine lights either, Go Figure?

zachs98chevy4x4

hi my 98 z71 has always had the service engine light on and for a few months it hasnt ran due to passlock and steerin column, i also did a complete tune up and when i went to get ti from the shop i notices on the way home the check engine light was flashing and it just seemed like it didnt have the power like normally, i got home and hooked my scanner adm it pulled a p0300 miss fire and p0452 low
output. does anyone know what it could be i have been told o2 sensors but at this point idk.

Cav1998

simple fix Just being honest here, your shop mechanic found a p300 code and reported it. That's IT? you need to fire your shop mechanic, or purchase the correct code reader the dealer uses to determine the source of the code report. Correct code readers cost around 8 to 15 K. sound like a generic code reader from parts store. Even my 500 $ code reader will not go past a generic code. Your head gasket is leaking, the catalytic converter is plugged or see the detailed list left by ( in2pro ) because he is right on the money. Multiple cylinder problem is an indicator of the PCM reading associated sensors and applying the correct fuel mixture. Steering column repair / and now your Getting the code? Some body at the shop bungled the repair or left some FOD in the steering column creating a short? Take it to a dealer, these kind of codes can get you or your family KILLED.


Take it to the dealer and have them diagnose it. they will find the problem. and you can decide at that time to put the cost of repair as a down payment on a new truck or certified-pre owned. Every thing you have described is exactly what I have experienced. I ended up replacing the cat on my98 cavalier. and on my 2005 Impala a dual cat system at a price that screamed "out of warranty", get a new car, wife wants this car fixed and spent $1700.00 to keep my marriage intact. Wish you the best in your problem quest.

BigTenFour

I got rid of my code P0300 by emptying the tank and refueling with midgrade fuel. it ran choppy like you described (chugging along like bad fuel being consumed)-bad fuel will cause a multiple misfire condition. Hope this helps.