Bad stuttering/sputtering under any load (Help, out of state)

[jross20]

Currently about 900 miles from home, on our way back. About an hour ago she started sputtering/stuttering/skipping under any load. We can maintain speed on flat ground, and higher rpm's greatly help, so dropping out of overdrive helps us get over hills.

When we are at a stop, I have to very gently baby the throttle other wise she just stumbles badly.

Any ideas? I'm thinking a fuel injector... Maybe? Worst of all, no codes at all.

2000 SR5 V6 Auto 4*4. 145k miles.

In the past year I've changed the spark plugs, wires, fuel filter, etc.

Any advice that may help us limp home would be worth many beers.

 

[zcruiser]

Did you use the dual-electrode plus or regular plugs?

 

[jross20]

Did you use the dual-electrode plus or regular plugs?

Duel electrode, also cleaned the MAF a few days ago as it stuttered once and I thought it may have been dirty from all the dust of Wyoming.

 

[MaineRunna]

Did you change the coil boots? These engines are famous for leaking spark through the spark plug & coil boots or out of carbon tracks on the spark plug insulators (porcelain). Could be a bad coil also. You'd have two dead cylinders if you have a bad coil. Is your check engine light on, is it flashing? Can you have it scanned somewhere?

 

[jross20]

Did you change the coil boots? These engines are famous for leaking spark through the spark plug & coil boots or out of carbon tracks on the spark plug insulators (porcelain). Could be a bad coil also. You'd have two dead cylinders if you have a bad coil. Is your check engine light on, is it flashing? Can you have it scanned somewhere?

Hey sorry for the delay, bad service out here.

I believe the wires had boots, they were oem. Also, no lights or codes, scanned with torque pro and at an auto store a little while ago.

As I drive it seems to mainly be a problem under 2000 rpm's, though I still feel it past there if the hill is steep enough, we just have to lose speed

 

[jross20]

The gf noticed but the passenger floorboard is excessively warm, enough to almost melt some m&M's in a bag. After thinking about it, I got to wondering if it could be the catalytic converter.

But I don't understand the relationship to a higher RPM being better and also the fact that fuel economy is not effected badly, in fact it is very good.

What are the symptoms of a bad cat on our rigs?

 

[Dieselchessy]

I’ve had similar due to a plug backing out, plug wire failing, coil boot issues, and bad coil.

With my rigs when the plug backed out it never popped a check engine. The other times I limped several miles before it ever popped the light.

If you’ve only got one cylinder not firing it might never pop the engine light.

Sounds like you’ve probably got 2 not foreign though. With only one cylinder out they still run pretty good.

 

[Dieselchessy]

Is your cat burning un-burnt fuel?

 

[snydmax]

Sounds like a misfire... are you getting a CEL? Mine ran just as you describe, gave a CEL and trouble code within 10miles as I limped home.

Trouble code identified Misfire on cylinders x,y (don’t remember which two) turned out to be a bad boot/wire

I kept the new coil I bought as a spare for emergencies


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[jross20]

I’ve had similar due to a plug backing out, plug wire failing, coil boot issues, and bad coil.

With my rigs when the plug backed out it never popped a check engine. The other times I limped several miles before it ever popped the light.

If you’ve only got one cylinder not firing it might never pop the engine light.

Sounds like you’ve probably got 2 not foreign though. With only one cylinder out they still run pretty good.

It's really hard to tell if it's a misfire or not. Really seems like it's not getting enough fuel maybe.

Would a misfire ease up at higher rpm's?

Is your cat burning un-burnt fuel?

Not sure, how would I check this?

Sounds like a misfire... are you getting a CEL? Mine ran just as you describe, gave a CEL and trouble code within 10miles as I limped home.

Trouble code identified Misfire on cylinders x,y (don’t remember which two) turned out to be a bad boot/wire

I kept the new coil I bought as a spare for emergencies


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When you say CEL, you're talking about codes right? Still no code as of last night. We are packing up now at this hotel at stayed at last night.

Did yours seem fine while cruising? Not under load? Did it ease up at higher rpm's?

If I remove the front 02 sensor and that fixes it, I presume that would confirm the cat, but I also presume I can't drive around with it removed right?

 

[LittleCaesar]

Any problems starting? If the kitty is clogged, you should be getting a po420. Also you can see if the post cat pipe is cool to the touch indicating a clogged cat (the post cat pipe is supposed to be hotter than the pre cat pipe in a normal working system).

What are your short and long term fuel trim numbers with TP?

 

[19963.4lsr5]

Unburned fuel from a missfire gets burned in the cat. Which can cause the cat to melt.

Your symptoms to me sound like a coil that’s bad. The higher the engine load the harder it is to spark the plug.

I’d buy a coil or three and new coil boots and start there.

To me it’s a pretty strong symptom of a weak coil that can know longer produce a spark at high engine loads/combustion pressures.


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[snydmax]

It's really hard to tell if it's a misfire or not. Really seems like it's not getting enough fuel maybe.

Would a misfire ease up at higher rpm's?



Not sure, how would I check this?



When you say CEL, you're talking about codes right? Still no code as of last night. We are packing up now at this hotel at stayed at last night.

Did yours seem fine while cruising? Not under load? Did it ease up at higher rpm's?

If I remove the front 02 sensor and that fixes it, I presume that would confirm the cat, but I also presume I can't drive around with it removed right?

CEL - “check engine light...” you won’t see any codes with an obd2 scanner unless this is on. I had no CEL initially, but it finally came on after idling for about 30 minutes es while we looked things over and then I drove it home, +/- 10 miles... the light came on before we made it to the house

Mine sounded terrible at idle, had no power, at “cruise” speed, no load, not on the throttle, it was less noticeable but I could definitely tell it was still misfiring.

The odor of fuel was also very prominent, easy to smell while the truck was idling and we were trying to diagnose... this was due to the fuel being dumped into the cylinder that was not being combusted as there was no spark.

I decided to stop and buy a set of plug wires and a coil on the way home that night, already had a set of plugs to put in, as it was getting late and wanted to see if it was something “easy.” Code confirmed my suspicion and we had her back on the road next morning.

I’d be very apprehensive to continue your journey with these symptoms, you could turn a minor repair into a major failure


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[snydmax]

It's really hard to tell if it's a misfire or not.

You can try to unplug each spark plug one at a time, see if that changes how the engine is running, an old school method.

Not sure if you can actually isolate them one at a time though with the way a single coil is shared by two plugs.


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[jross20]

Finally got codes, still limping carefully. 450 miles to home

p0300 p0303

 

[jross20]

CEL - “check engine light...” you won’t see any codes with an obd2 scanner unless this is on. I had no CEL initially, but it finally came on after idling for about 30 minutes es while we looked things over and then I drove it home, +/- 10 miles... the light came on before we made it to the house

Mine sounded terrible at idle, had no power, at “cruise” speed, no load, not on the throttle, it was less noticeable but I could definitely tell it was still misfiring.

The odor of fuel was also very prominent, easy to smell while the truck was idling and we were trying to diagnose... this was due to the fuel being dumped into the cylinder that was not being combusted as there was no spark.

I decided to stop and buy a set of plug wires and a coil on the way home that night, already had a set of plugs to put in, as it was getting late and wanted to see if it was something “easy.” Code confirmed my suspicion and we had her back on the road next morning.

I’d be very apprehensive to continue your journey with these symptoms, you could turn a minor repair into a major failure


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Ah shit, I don't really know what else to do. I can stop and swap the coil to see if that's it

 

[snydmax]

Ah shit, I don't really know what else to do. I can stop and swap the coil to see if that's it

P0300 and p0303 are misfire... if it were you I would hit up the next parts store you come across and start pulling plug wires, plugs, coils.

Time lost there will be made up quickly of you get the problem solved and can travel at full speed

I had an obviously meted plug wire boot


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[snydmax]

P0300 and p0303 are misfire... if it were you I would hit up the next parts store you come across and start pulling plug wires, plugs, coils.

I had an obviously meted plug wire boot


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You may cook your cat(s) with all that fuel dumping through the exhaust


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[snydmax]

Finally got codes, still limping carefully. 450 miles to home

p0300 p0303

P0303... cylinder 3? Start there by checking coil/boot/plug. If your not smelling a fuel rich exhaust, could be an air/fuel/vacuum/injector issue rather than electrical

If your not misfiring on cylinder 4 as well, it’s more likely the boot or plug at cylinder 3... does that make sense?


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[19963.4lsr5]

Missfire detection is poor on our rigs. I had a bad coil on the 97 Puppy Hauler and she drove it 20 miles home from Reading PA with it shaking at intersections and having that off exhaust tone from dropped cylinders.

It was a bad coil and driving it from my house to my garage where I worked on my stuff it only shown a missfire code turning into the driveway 2 miles down the road.

You will melt your cat if you don’t solve this soon.

I’d buy a new coil and a new wire set that includes the coil boots and install the complete wire set and the coil for the cylinder that fires number 3 cylinder. It’s where I’d start.


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