6.0 with P0300 and loss of power

[ErikSS]

ok, here is the skinny. I got gas one evening, and the next morning my truck hada bad miss and loss of power. I pulled a ton of codes. P0300 Random Multiple Misfire is the only recurring of the codes but it's worth mentioning that the Catalyst System Malfunction Bank 1 code popped up too.

At an idle, the miss is slight but noticable if you'r listening to the engine. At WOT there is almost no power.

So far I have:
Replaced plugs and wires. (Delco plugs and Carquest liftime wires)
Checked each coil for spark. (all strong)
Compression test (all within 10%)
Cylinder drop test (each cylinder made a change)
Fuel pressure test (60psi with engine on and off)
Cleaned throttle body and washable air filter
Checked fuel trim (Dave did this for me and says they are right on)
Checked O2 sensor data (Dave did this for me and says they are right on)
Snugged my intake manifoled bots (SS forum recommended)
Misted the intake, hoses, and brake boster with start fluid (no change)
Checked temerature of the converters. Compared left to right, before and after cat temps
Unhooked battery to reset

I'm running out of ideas. Anybody got ideas?

[mikekey]

Catalytic converter, that's what I told you.

[ErikSS]

Catalytic converter, that's what I told you.

Would there be a change in Cat temperature between sides of the engine? and before and afte the cat? Honest question... I can see it possible either way.

[v7guy]

Bad gas?

[mikekey]

Actually drive it, if the cat is clogged it will heat up and glow if you run it long enough. If not, then try the Cam position sensor, bad gas possible, but more unlikely these days unless their was moisture in the line.

[ErikSS]

Actually drive it, if the cat is clogged it will heat up and glow if you run it long enough. If not, then try the Cam position sensor, bad gas possible, but more unlikely these days unless their was moisture in the line.

I drove it 25 mins to work. No glowing. No major difference side to side.

[Moots1288]

Bad gas. That's what happened to my truck.

[v7guy]

I'm skeptical of the cam sensor, the misfire code comes from a reading of the crank sensor. It picks up a differwnce in the rotation of the crank and then sends the code for the misfire. It's relatively uncommon for the crank sensor to kick the bucket from the reading I've done over the years.

[dvanbramer88]

Did you try a new cap and rotor?


in highschool, the girl I was dating at the time got bad gas, and her car acted exactly like it had a clogged cat. Ran rough with a miss, zero power, a tinge of black smoke in the exhaust under heavy load. Turned out to be bad gas.


For you, its a toss up for either bad gas or a clogged cat. If you don't have a bad cat yet, running it with the miss long enough could kill your cat(s) and O2 sensors.

[mikekey]

Man, I just had bad gas yesterday, I sat on the toilet for awhile, but it just felt like a million knives in my stomach.

[Moots1288]

Did you try a new cap and rotor?


in highschool, the girl I was dating at the time got bad gas, and her car acted exactly like it had a clogged cat. Ran rough with a miss, zero power, a tinge of black smoke in the exhaust under heavy load. Turned out to be bad gas.


For you, its a toss up for either bad gas or a clogged cat. If you don't have a bad cat yet, running it with the miss long enough could kill your cat(s) and O2 sensors.

in high school huh. Last year?

[dvanbramer88]

Everybody shitting up Erik's thread...

Mike: I know your pain.

Matt: 2.5 going on 3 years out of highschool.

[djthumper]

moisture in the fuel... Bad gas

[dvanbramer88]

It's like 2 bucks, give it a shot?

Yellow is the original, red is a year-round formula with injector cleaner.

[ErikSS]

Cat temps are holding steady at 1400 on the highway. From what I understand, that's within good standards. I burned up the last of that tank of gas and filled up 20 gallons of 93 octane. No change at all. None.

EDIT: I put 2 bottles of that Heat in my tank the night before.
I am still getting the P0300 code. But I am also getting a P0101 code for the MAF sensor now.

[Norcrosski]

fuel filter? and pressure test fuel pump. My truck (dodge dakota with a 318) had good gas about 6 months ago and pump couldn't keep with demand it would drop 20 psi fuel pressure under load.

[ErikSS]

fuel filter? and pressure test fuel pump. My truck (dodge dakota with a 318) had good gas about 6 months ago and pump couldn't keep with demand it would drop 20 psi fuel pressure under load.

I thought about that. My truck doesn't have an external fuel filter. Only the sock in the tank. It pushes 60psi with only the key on, and with the engine at an idle. How did you test it under load?

[DustinC1989]

Clogged injectors?

[ErikSS]

Clogged injectors?

It's possible. It would have to be more than one. Would I pull the fuel rail and look at them? Would I be able to see if they are clogged?

[dvanbramer88]

http://www.obd-codes.com/p0101