Code 300 - random misfire

jd

Hero Member
Joined
Jan 14, 2007
Messages
521
Likes
27
Points
18
#16
I have heard (seen on TV actually, Motor Week) that if a fuel injected engine has a Fly By Wire (no mechanical linkage) accelerator pedal, the way to clean both sides of the Throttle Plate while ("whilst" for our Beloved Canadians, Hi, nb2!) is to turn Ignition ON and have an assistant hold the pedal down with Engine NOT running... The PCM will open the throttle plate. If we force it open, PCM may set a Code, saying Pedal and Throttle positions don't match.

Did a little Stinger Research and it seems that only Honey Bees have a barbed stinger that makes them a one-sting critter, pulling the bee's venom sac out and leaving the stinger in our hide. Actual Bees only. Try to work it out with a scraping action to avoid squeezing the last of the venom out before the barb is out. Wasps don't and Hornets (aka Yellow Jackets) don't leave the stinger, but the Hornet's sting is worse for most of us. Article says "If stung by a Hornet, Run! Same one(s) can sting again."

Speaking of Language, I think there's a Yellow Jacket brand of air conditioning tools. Or, for $139 with free shipping, you can get a Yellow Jacket for your iPhone. It's case, backup battery, and isn't Yellow. The sting implication comes from its Built in....TASER!
 
Joined
Mar 1, 2002
Messages
3,542
Likes
55
Points
48
Location
Kentucky
#17
Yellow Jacket Iphone case? DO NOT operate phone while sleepy or intoxicated!
 
Joined
Aug 28, 2007
Messages
4,732
Likes
24
Points
38
#18
Youngest daughter was buying gas from a gas station six blocks from us, not only misfires, but complete stalls, told her a million times not to buy gas from them, has as water, but dad, its closest!

When stalled, grabbed my fuel pump tester, drove out, knew where the fuel pump relay was, jumped it and poured out water, was good to go again.

Also ignorant, took my motorhome north last fall, had two gas stations, a Shell and a Holiday, chose Shell, after driving about ten miles, stalled. Pulled to the side of the road, crawled under, disconnected the fuel filter and had my wife switch on the electric fuel pump. transparent type, could see the water flow out. Dark, glad I had a flashlight. Then after a few rough starts was good to go again.

Talked to my son about this, he goes north all the time, everybody knows that Shell gas station has water in it, well except me.

Is it possible your gas station is selling you water for over three bucks per gallon?

Water in gas is a major problem, all the airports I was serving had to switch to above ground tanks, should do the same for gas stations. Even my son picked the wrong gas station, a Mobile near his home. On a trip to Milwaukee, purchased a couple cans of Heat and tossed that in, helped a little, but got us home.
 

abrad

Full Member
Joined
Feb 20, 2007
Messages
149
Likes
2
Points
18
Location
New York
#19
This car will probably haunt me even after death!

Car now has a cylinder 1 misfire.

Plug 1 had some crud on it, so I replaced all 4 plugs as a potential cheap fix, cleared the code, came right back.

Swapped coil 1 with coil 2, cleared code and #1 came right back.

Checked compression, 3X each cylinder
1- 170,175,170
2- 170,160,170
3- 150,145,150
4- 160,155,160
Then, after buttoning everything back up, I checked again. Now it shows misfire on 2 which is what I swapped 1 with! Going to get a new coil pack for that to be on safe side, but still need to figure oil consumption...

Car has also been going thru some oil (I cleaned pcv valve about a month ago). Some oil pooled around plug boots on #2&3. Looks like some oil also seeping out by fuel injectors.
Wife and stepson have run car a few times low oil (needed 3 quarts to fill up once!). Maybe now they will understand why I yell at them!!!

1quart every week or two. I noticed some oil by the injectors and also around the boots on coil 2&3. That "might" be due to oil being spilled on top while filling. I've cleaned as much up as possible. Will have to check a bit closer over the next couple weeks.

Valve cover gasket might also be an issue, but I need time to get in there and clean that section out a bit better (really tight in there!).

This is what’s so frustrating. No oil leaks on the ground, just “some” oil on the side of the engine. It does seem to be burning some oil - grey exhaust. Might just put a new pcv valve in. Cleaned it out about a month ago. Don’t remember when I last changed it.

I am wondering if it might be a valve issue. Not liking that prospect as I’ve never done one of those before!

Trying to figure out stupid simple stuff first before looking at doing major work.

Thanks for the help!
 

abrad

Full Member
Joined
Feb 20, 2007
Messages
149
Likes
2
Points
18
Location
New York
#20
Also, I think I may have "found" the random misfire that has been a continuous problem for awhile... Had a tech mention that there "might" be a hole in the pickup tube, at about the half tank mark. When the fuel level gets below the hole, air gets sucked in which lowers the amount of fuel and "might" cause a misfire. Told the wife I really don't feel like dropping the fuel tank and pulling the pump if keeping the tank above 1/2 will "solve" the problem!!!
 

grcauto

Hero Member
Joined
May 29, 2014
Messages
517
Likes
32
Points
28
#21
Also, I think I may have "found" the random misfire that has been a continuous problem for awhile... Had a tech mention that there "might" be a hole in the pickup tube, at about the half tank mark. When the fuel level gets below the hole, air gets sucked in which lowers the amount of fuel and "might" cause a misfire. Told the wife I really don't feel like dropping the fuel tank and pulling the pump if keeping the tank above 1/2 will "solve" the problem!!!
Whoever that tech is they need to go to school and become a real tech or learn to keep their lack of wisdom to themselves. Think about it.....Is there a 'pickup tube' for the fuel pump that runs vertically in the tank?
 

abrad

Full Member
Joined
Feb 20, 2007
Messages
149
Likes
2
Points
18
Location
New York
#22
Whoever that tech is they need to go to school and become a real tech or learn to keep their lack of wisdom to themselves. Think about it.....Is there a 'pickup tube' for the fuel pump that runs vertically in the tank?
 

grcauto

Hero Member
Joined
May 29, 2014
Messages
517
Likes
32
Points
28
#24
The sending unit has nothing to do with fuel delivery. It's just a variable resistor with a sweep arm and a float on the other end. It cannot suck air. The fuel pump is at the bottom of the tank and it pushes the fuel up and out of the tank. If that area between the pump discharge and the line out the top of the tank gets a hole in it at about the halfway mark what do you think will happen? Will the pump push fuel out the hole or will air enter in by overcoming the PRESSURE of the fuel? The hole, which is under pressure from the fuel, will push fuel out the hole and pressure will drop. This will be the result at all times regardless of how much fuel is in the tank.
 

abrad

Full Member
Joined
Feb 20, 2007
Messages
149
Likes
2
Points
18
Location
New York
#26
That much is true. I just don’t know the exact location of the pump relative to the intake. If it’s on the bottom, then yes it would be pressurized all the way. If it was further up and the pickup tube was lower, then there would be suction. Either way, above half a tank no random misfire. Below half a tank and she gets the random misfire.

At this point, I don’t really care to “fix” the problem as much as I prefer to just prevent it from occurring.

Really don’t feel like removing the gas tank to go on a fishing expedition if I don’t absolutely have to! That would likely open up a whole nother can of worms!
 

grcauto

Hero Member
Joined
May 29, 2014
Messages
517
Likes
32
Points
28
#27
That much is true. I just don’t know the exact location of the pump relative to the intake. If it’s on the bottom, then yes it would be pressurized all the way. If it was further up and the pickup tube was lower, then there would be suction. Either way, above half a tank no random misfire. Below half a tank and she gets the random misfire.

At this point, I don’t really care to “fix” the problem as much as I prefer to just prevent it from occurring.

Really don’t feel like removing the gas tank to go on a fishing expedition if I don’t absolutely have to! That would likely open up a whole nother can of worms!
Take and look at fuel trims during the misfire and see what's going on. If it's running rich pinch off the hose from the purge valve to the intake and see if it goes normal while pinched.