Question 2004 Pace Arrow 36B bad running 8.1 Vortec

[Scooterfan]

You said you filled up and it ran well for an hour or more...Hmmm...I don't want to dismiss all the above potential issues, but don't ignore the possibility you have a dirty fuel problem. Being a boater I'm familiar with bad fuel issues. Could be water, particulate(s), rust, octane, or many other fuel related problems. Make sure your filter is clean (and new) and if you can and if it is water, search drying agents to remove it. Hope you find the reason for your poor performance.

 

[DHudson]

You said you filled up and it ran well for an hour or more...Hmmm...I don't want to dismiss all the above potential issues, but don't ignore the possibility you have a dirty fuel problem. Being a boater I'm familiar with bad fuel issues. Could be water, particulate(s), rust, octane, or many other fuel related problems. Make sure your filter is clean (and new) and if you can and if it is water, search drying agents to remove it. Hope you find the reason for your poor performance.

Sure wouldn't hurt to add a couple cans of SEAFOAM to the gas tank.

 

[Newton36B]

Sure wouldn't hurt to add a couple cans of SEAFOAM to the gas tank.

Bought some Seafoam today, can't hurt !

 

[Newton36B]

I'll take a look today, it would be great to find the problem so I can fix it. Thanks for your input !

Two things. It sounds like you have a ignition coil failing and or the plug wires are failing.
The coil will act like you described getting worse the more it is run. Cools down does ok for a while.
Plug wire will act same way. Plug wires tend to show up more under a load like pulling up a hill than just cruising on level ground.
I would replace both and probably the s/plugs Distributor cap, and rotor, while your there

Last night I ran the engine after dark with the doghouse cover off and I caould see the flash from the spark on coil number 5, I assume I can replace just that coil and see if it corrects the problem ?

 

[DHudson]

Last night I ran the engine after dark with the doghouse cover off and I caould see the flash from the spark on coil number 5, I assume I can replace just that coil and see if it corrects the problem ?

yes sir.

 

[DHudson]

For some reason, I was thinking yours still had a single coil. Sorry. From your symptoms it still sounds like a bad coil (s).
Some cylinders misfiring on a engine will affect the engine more than other cylinders. It's has do do with the was cylinders are phased in the firing order.
A bad coil(s) on yours could still very well be the problem.
These are kinda hard to diagnosis, but if you have a catalytic converter stopping up, it may act like your problem. Someone that has a scan tool and knows how to read the live data can usually look at the O2 sensor data and determine if a converter is stopped up. Not always, but often it will throw a code of "low efficacy" for the converter, ( though that tends to be another problem than a bad converter)
Another possibility, if you have trash in your fuel tank, while you drive, sometimes debris will be sucked up around the screen for the fuel line and starve the engine for fuel. You stop and it falls away. You usually have to drop the tank and clean it out if that is the case. I don't think this is your problem though.

Here is what I would do.
Replace the coil you saw arcing.
Add 4 or 5 cans of Seafoam if your 1/2 a tank or more fuel of fuel. This will help eliminate water AND clean the injectors. 1 can will not do anything in that big of tank.
If it still acts up, Get someone to scan the system and look at the individual cylinder misfire chart.
Say #8 shows miss fires.
Plug the plug Does it look fouled (black carboned up, wet)
You said you replace the wires. (hope the were the cheapest Autozone ones). They are crap. You may have fixed the problem with wires and just need to replace plug that was damaged by bad wire or coil.
Any cylinder that shows a misfire in the data chart needs attention.

The things that affect a cylinder fire are: (Keeping in mind your symptoms) Runs ok for a while starts missing pulling grades, looses power, stop cool off and runs ok a while
Spark Plug
Spark plug wire
Coil
Fuel injector.

Missing pulling a grade means some thing in the electrical side of the ignition is breaking down under a load. Plugs, wires, coil
Fuel starvation might also cause it. Maybe
O2 sensors should be reading "lean" if this is the case.
Did you replace the fuel filter?
Do that if not. Those filters are good for a max of 30,000 miles. Crappy gas, 12,000 miles or less.

As diagnostic scan to will tell a tech where to look if they know how to read the data.
Without throwing a lot of parts that are not needed. It's sad but there seem to be less and less Techs that know how to properly diagnose problems today.
They see a code and throw a part at it.

 

[Kevin D Pem]

You can throw a lot of cash at it if you want. Have you yet put a code reader on the rig yet? driving into an auto parts store and they will do it for free. Codes are a tool not an answer however missing will show with the code reader and tell you what cylinder is the problem. It won't tell you if the coil,wire,spark plug, or low voltage wire or computer. however it is the way to reduce the amount of funds you throw at it.

 

[Newton36B]

For some reason, I was thinking yours still had a single coil. Sorry. From your symptoms it still sounds like a bad coil (s).
Some cylinders misfiring on a engine will affect the engine more than other cylinders. It's has do do with the was cylinders are phased in the firing order.
A bad coil(s) on yours could still very well be the problem.
These are kinda hard to diagnosis, but if you have a catalytic converter stopping up, it may act like your problem. Someone that has a scan tool and knows how to read the live data can usually look at the O2 sensor data and determine if a converter is stopped up. Not always, but often it will throw a code of "low efficacy" for the converter, ( though that tends to be another problem than a bad converter)
Another possibility, if you have trash in your fuel tank, while you drive, sometimes debris will be sucked up around the screen for the fuel line and starve the engine for fuel. You stop and it falls away. You usually have to drop the tank and clean it out if that is the case. I don't think this is your problem though.

Here is what I would do.
Replace the coil you saw arcing.
Add 4 or 5 cans of Seafoam if your 1/2 a tank or more fuel of fuel. This will help eliminate water AND clean the injectors. 1 can will not do anything in that big of tank.
If it still acts up, Get someone to scan the system and look at the individual cylinder misfire chart.
Say #8 shows miss fires.
Plug the plug Does it look fouled (black carboned up, wet)
You said you replace the wires. (hope the were the cheapest Autozone ones). They are crap. You may have fixed the problem with wires and just need to replace plug that was damaged by bad wire or coil.
Any cylinder that shows a misfire in the data chart needs attention.

The things that affect a cylinder fire are: (Keeping in mind your symptoms) Runs ok for a while starts missing pulling grades, looses power, stop cool off and runs ok a while
Spark Plug
Spark plug wire
Coil
Fuel injector.

Missing pulling a grade means some thing in the electrical side of the ignition is breaking down under a load. Plugs, wires, coil
Fuel starvation might also cause it. Maybe
O2 sensors should be reading "lean" if this is the case.
Did you replace the fuel filter?
Do that if not. Those filters are good for a max of 30,000 miles. Crappy gas, 12,000 miles or less.

As diagnostic scan to will tell a tech where to look if they know how to read the data.
Without throwing a lot of parts that are not needed. It's sad but there seem to be less and less Techs that know how to properly diagnose problems today.
They see a code and throw a part at it.

Yes I think the two O2 sensors may have been a waste of money, I just put the coil on but won't know if it improves the situation until I drive it for awhile, I think I'll replace the plugs while I'm at it, the plug wires are Napa premium, Belden wires. I appreciate your advice.

 

[DHudson]

Wish I could be more concrete about suggestions, but without being there, I just having go off past experience.

 

[Newton36B]

Wish I could be more concrete about suggestions, but without being there, I just having go off past experience.

I appreciate the input, I have an appointment for August 4th, but I disconnected the battery when I installed the coil, now the check engine light is off, may have cleared the fault codes ?