engine codes (1 Viewer)

[warren]

About six months ago my engine light came on for about a day and went off. I hooked up the trusty dusty computer coder reader and it said:

P0300 Multiple cylinder misfire
P0302 Cylinder 2 misfire
P0304 Cylinder 4 misfire

fast forward to last night, engine light comes on when leaving dinner. Same codes.

Truck is running fine and there does not seem to be miss. Cleared the codes again.

If it was a coil going bad, would I have multiple cylinder misfires? Seems like it should just be one code for one bad coil. If two are going bad, the rig should run terrible. Give me some input please.

Warren

 

[warren]

Bueler? Bueler?

 

[Travis351]

Since it is intermittant and seems to fix itself, could we suspect bad fuel? I too think you would notice a multiple cylinder misfire...

 

[calamaridog]

Possible trouble areas according to the FSM

-open or short in engine wire
-connector connection
-vacuum hose connection
-ingnition system
-injector
-fuel pressure
-mass air flow meter
-engine coolant temp. sensor
-compression pressure
-valve clearance
-valve timing
-ECM

Year and mileage on vehicle? Age of plugs? Checked the connections yet?

 

[warren]

it is a 1999 with 137000 miles. I have no records it from the previous owner. It seems to be taken care of and had oem oil filter on it when purchased. The plugs have about 40,000 on them.

The valve timing comment worries me. I do not know if the timing belt has been changed or not.

the vehicle has never seemed to run bad when the problem occurs.

I will wiggle some connections and see what happens.

Any suggestions are appreciated.

Warren

 

[Travis351]

Can you duplicate it at a specific RPM? Does it only happen when it is warming up?

There are 6 pages of troubleshooting in the FSM on this taking you down the typical ignition/fuel troubleshooting stuff if you can duplicate the problem.

Lack of or use of improper fuel
Wire Harness Loose
Vaccum Hose Broken
Carbon on spark plug
Coil...check for spark
Check voltage of ECM terminal for injector of failed cylinder
Oscilloscope inspection
Check resistance of injector of misfiring cylinder
Check Fuel Pressure
Check Injecter injection
Check Mass air flow meter and engine coolant temp senser
Check compression pressure.

You might need the FSM for this one...my scanner isn't working right.

 

[calamaridog]

Honestly.

I would clear the codes and see if they come back in 6 more months.

 

[Travis351]

Honestly.

I would clear the codes and see if they come back in 6 more months.

Sounds like a good plan to me.

 

[NMuzj100]

Looks like a bad coil pack. Usually a single coil pack fails but the misfire detectors are so sensitive that neighboring cylinder detectors also trip (4 and 2 are adjacent in the right bank). You can troubleshoot by trading a coil pack from the indicated cylinders to a "good" one and see if the codes move. (move 4 to 7)

Coil pack problems

 

[LEXUSBEN]

About six months ago my engine light came on for about a day and went off. I hooked up the trusty dusty computer coder reader and it said:

P0300 Multiple cylinder misfire
P0302 Cylinder 2 misfire
P0304 Cylinder 4 misfire

fast forward to last night, engine light comes on when leaving dinner. Same codes.

Truck is running fine and there does not seem to be miss. Cleared the codes again.

If it was a coil going bad, would I have multiple cylinder misfires? Seems like it should just be one code for one bad coil. If two are going bad, the rig should run terrible. Give me some input please.

Warren

Quick rundown,
p0300 - less than 18% misfire
all individual cyl codes 18-50%, 50 is dead miss.

best advice, need to hook up toyota scan tool (unfortunately)
it will tell you the misfire percentage on each cyl. Higher percentage is most likely the problem. I would bet you either have a failing injector or coil pack and it is affecting the cyl next to it because of the miss. So either #2 or #4 is the root cause. Good luck.