Problem with engine stumbling

[Bloody_Knuckles]

My son has a 2007 Ram 1500 quad cab with a 4.7l engine. The problem arises that when he accelerates hard or the engine wpeed gets above 4500, it begins to stumble. No codes. I'm thinking it's a fuel delivery problem but would like to see other people's opinion.

 

[Karlsweg]

Sounds like it’s running out of fuel. Did you check the pressure?

 

[Bloody_Knuckles]

Can you check it with an OBD reader?

Never mind. I found a fuel pressure parameter in the OBD reader.

 

[Bloody_Knuckles]

Update. It throws a check engine code of P0344 (intermittent camshaft position sensor) when it hits about 4500 rpm and dies then restarts immediately. He replaced the CMP sensor a couple of years ago, but I'm thinking it is a cheap Chinese POS because it will run fine at lower rpm. Thoughts?

 

[HemiLonestar]

Update. It throws a check engine code of P0344 (intermittent camshaft position sensor) when it hits about 4500 rpm and dies then restarts immediately. He replaced the CMP sensor a couple of years ago, but I'm thinking it is a cheap Chinese POS because it will run fine at lower rpm. Thoughts?

Sensors I have found you don't wanna cheap out on. Try an OEM one and see what happens. Check the wiring to it just in case as well.

 

[gofishn]

Had this problem on a old CHevy and it turned out to be teh catalytic Convertor bogging things down, throwing codes.
None of them an exhaust code though, oddly enough.

Could not figure it out so took it a guy I know, hetells me what he thinks, I disagree.
He sticks a big ass screwdiver into the cat and lo and behold, it ran better. Bigger teh hole, better she ran.

Humble Pie still tastes crappy, by the wway.

 

[Bloody_Knuckles]

Also, the oxygen sensors fluctuate wildly. Is that normal?

 

[gofishn]

Also, the oxygen sensors fluctuate wildly. Is that normal?

That makes me think it might be exhaust not being urged properly, due to clogged cats.
Easy peasy way to find out. Remove a sensor, if ther is one, between exhaust maniolfd and Catalytic convertor.
WIll be loud but if engine runs better, there's your problem.

DOn;t do what my guy, just poke holes in the damn thing. He was Confident that was teh issue. WE are not confident it is teh issue, for you, so do not do anything that cannot be repaired, easily.

 

[Bloody_Knuckles]

The engine idles and runs fine up to about 4500 rpm.

 

[Fast69Mopar]

Also, the oxygen sensors fluctuate wildly. Is that normal?

The Upstream oxygen sensors, the 1/1 and the 2/1 oxygen sensors, do switch from lean to rich. You will see the voltage switch from low to high. This is completely normal for the upstream sensors. Now, for the Downstream sensors, the 1/2 and the 2/2, are not supposed to switch from lean to rich or low voltage to high voltage. The sensor voltage is supposed to remain as stable as possible.

 

[scott lass 18]

Had this problem on a old CHevy and it turned out to be teh catalytic Convertor bogging things down, throwing codes.
None of them an exhaust code though, oddly enough.

Could not figure it out so took it a guy I know, hetells me what he thinks, I disagree.
He sticks a big ass screwdiver into the cat and lo and behold, it ran better. Bigger teh hole, better she ran.

Humble Pie still tastes crappy, by the wway.

my old chevy had a cap plug open it bee bee s came out blow them all out put cap plug back on ran so much better ya it was best thing i did !

 

[Bloody_Knuckles]

The Upstream oxygen sensors, the 1/1 and the 2/1 oxygen sensors, do switch from lean to rich. You will see the voltage switch from low to high. This is completely normal for the upstream sensors. Now, for the Downstream sensors, the 1/2 and the 2/2, are not supposed to switch from lean to rich or low voltage to high voltage. The sensor voltage is supposed to remain as stable as possible.

Good. The downstream were stable.

 

[JohnnyMac]

Could just need a simple tune up as well. I'd check all ignition components.

 

[Bloody_Knuckles]

I'm thinking the loop that controls the fuel mixture is wonky. My degree is in electrical engineering and a specialty in control loops. If I could get access to the PID paramters, I'd bet they need tweaking.

 

[LoneWolf3574]

I'm thinking the loop that controls the fuel mixture is wonky. My degree is in electrical engineering and a specialty in control loops. If I could get access to the PID paramters, I'd bet they need tweaking.

This is how custom tunes are made people.

 

[10 Break]

The Upstream oxygen sensors, the 1/1 and the 2/1 oxygen sensors, do switch from lean to rich. You will see the voltage switch from low to high. This is completely normal for the upstream sensors. Now, for the Downstream sensors, the 1/2 and the 2/2, are not supposed to switch from lean to rich or low voltage to high voltage. The sensor voltage is supposed to remain as stable as possible.

Kind of interesting to watch the live data on a scanner. Raw exhaust going in and cooked by the cats coming out.

 

[Aviopro]

Fast69 thats what I thought. I have a 99 1500 5.9 that has lost power and idles rough once its warmed up. on occasion ive heard rattling in the cat but havent in awhile.
i hooked my scanner up and it shows the downstream sensor fluctuating as much as the upstream sensor. From what I've read this tell me the cat isnt doing its job.
What say you?