Smooth startup followed by loss of power

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glipman

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Ram Year
1998
Engine
Magnum 5.9
5.9 1998 1500, it starts fine and idles alright but once I get going at random points it becomes so bogged down it's undrivable, idling just barely above 250 rpms. It has happened more recently when it is wet outside, hell of alot of rain in the north of Indiana lately!
I don't know how well it was taken care of before I got into it.
Oil level is good
Coolant level is good
Ran Heet through it and it seemed to clear up but came right back.
Used battery in it about 3 years old
It has cats but there is no rattle on start up and has been handling highway speeds with no problem.
When the rough idle occurs I try to give it gas and it bogs down even more, almost like it's flooding. This makes me think ignition system might need a tune or it's running to lean, it makes an air sucking noice from the intake at full throttle and threatens to die on me.
I'm just curious as to why it's an intermittent problem and not a constant issue. Anyone have any ideas or need more info?

"inspirational quote" - someone
 
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glipman

glipman

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I've read that the pickup and the ignition (resistor?) Before the cap can cause this problem if they begin to go out but don't quit immediately

"inspirational quote" - someone
 
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glipman

glipman

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Also this issue happens while driving not just at stops but is more frequent when at stops

"inspirational quote" - someone
 

Ram1X4

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In my limited experience, you are describing a loss of spark. Check all plug wire and coil connections for damage and moisture. I have a buddy that literally had a wet coil connection cause a similar problem on an F150. Saying it's been raining a lot is very suspect.
 
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glipman

glipman

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In my limited experience, you are describing a loss of spark. Check all plug wire and coil connections for damage and moisture. I have a buddy that literally had a wet coil connection cause a similar problem on an F150. Saying it's been raining a lot is very suspect.
Alright, it has boggled me all day but I kept coming back to this as well. I'll check after work and update on the issue, moisture plus electrical equals no beuno [emoji12]

"inspirational quote" - someone
 

Yeret

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1999
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5.9 Magnum
I wouldn't be so quick to dismiss the catalytic converter. When my first one plugged up, it didn't make any kind of noise at all. The exhaust didn't even have that sulfur smell.

Foolproof test for the cat is to let it warm up then place the truck in park and give it gas. The engine should freely rev north of 3,000 RPM. If it hits a wall and won't rev past that, you almost certainly have a plugged cat.
 
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glipman

glipman

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I wouldn't be so quick to dismiss the catalytic converter. When my first one plugged up, it didn't make any kind of noise at all. The exhaust didn't even have that sulfur smell.

Foolproof test for the cat is to let it warm up then place the truck in park and give it gas. The engine should freely rev north of 3,000 RPM. If it hits a wall and won't rev past that, you almost certainly have a plugged cat.
Okay, would a plugged cat cause intermittent problems and not be constant? Regardless I'll try it but curiosity at this point

"inspirational quote" - someone
 

dudeman2009

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The Cat is certainly something to keep in mind as it can cause problems similar to this.

An easy thing to test is the ignition coil. When they start to go bad they cause strange problems that are hard to track down based on symptom alone.

To test the ignition coil get a multimeter and probe between the two pins on the bottom of the coil. You should read about 1 ohm. Then probe between the tower on top and one of the pins below, you should get anywhere from 12K-15K ohms.

I'd do this test both cold and after you've warmed the truck up, the two measurements shouldn't be more than 10% off.

The cam sensor is under the distributor cap and shouldn't need to be messed with. It's a hall effect sensor and is quite robust, it rarely goes bad.
 
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glipman

glipman

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The bottom pins fluctuate between 1-.5 ohms top reads at a fluctuating 14kh

"inspirational quote" - someone
 

dudeman2009

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The bottom pins fluctuate between 1-.5 ohms top reads at a fluctuating 14kh

"inspirational quote" - someone

If it reads about that both when cold and hot, then the ignition coil is likely good.
 
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glipman

glipman

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If it reads about that both when cold and hot, then the ignition coil is likely good.
It turned out to be the ignition coil, it had a hairline crack along the bottom end where water was going up into it. Went to the auto parts store to grab one and ended up with a full ignition tune up. Oh well I guess, at least now I know I need to do an upper intake gasket because cylinder 8 is fowled and my o2 sensors are fouled up as well! But my cats aren't clogged. Silver linings and more to do lists lol.
Thanks for the help guys! One problem down 2 more to go!

"inspirational quote" - someone
 
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