99 Ram: intermittent loss of power

[kevm14]

I think this thing is going to need a fuel pump soon.

In b4 "are you sure the power loss is intermittent?"

[bill25]

Or "this thing sucks except intermittent bursts of power:...

[kevm14]

I checked the fuel pressure. It was around 45 psi and not effected by vacuum. I think this truck has no fuel filter and the regulator is part of the in tank pump assembly. The whole assembly including level sender is like $120 so that's pretty cheap.

I couldn't make it act up when the fuel pressure gauge was on it (of course). Maybe I will just toss the gauge in the truck and next time it acts up, test the pressure.

At a light I tried to brake torque it and actually started a burnout, shockingly. The gearing on this thing is still too tall imo. 3.55 sounds good but if you do a 2-1 at like 20 it still has to accelerate a bit before it even hits the torque peak.

[kevm14]

https://www.rockauto.com/en/moreinfo.ph ... 137&jsn=23

This one is $113.79 which is not bad at all considering it is a complete assembly. Even for just a pump the price is reasonable, actually.

Before I jump into this though I do need to rule out other causes, like electrical. Maybe I'll do some research and see what is typical.

I also really need to see fuel pressure drop when the problem is happening so I at least focus on the right subsystem.

[kevm14]

This was a terrible read.

https://www.cargurus.com/Cars/Discussio ... 1_ds548232

Mainly because it was all people having no idea what is wrong but a lot of similar symptoms. I learned that the intake gaskets are known to go to crap on these, and that may explain my oil consumption. I also learned that computers can go bad...

Like I said, if I can get it to act up and have steady fuel pressure, that would be a great lead. Problem is, I can only really check fuel pressure in park and it always idles fine. That's why I was brake torqueing it in my driveway but found nothing.

[kevm14]

Just drove all over the place and beat on it quite a bit. No issues. I will say the top end power doesn't feel right but it could be normal.

I feel like the symptom happens after a bit of a hot soak. So I will try to go out in another few minutes and see if that does anything. I'm kind of leaning away from the fuel pump at this time though I have the pressure gauge in the truck now, ready to be hooked up.

[kevm14]

That didn't do it, either. I think I need warmer weather. I don't know what kind of clue that even is.

I guess I'll ignore it for now.

[kevm14]

Drove to transfer station. No issues. Curious what happens as the weather warms. It really feels like a fuel starvation but I guess it could be ignition or something else.

[kevm14]

It may be the cat.

Got misfire codes for multiple random, cyl 1, 3, 5, 6 under WOT. Won't really rev above 4,000 rpm. Even a free rev sometimes. Exhaust smells funny. Cat is rattling. I may have seen powdered/liquefied cat ceramic come out of the exhaust also.

So this may be my issue.

Fuel pressure during this stuff looked perfect. So there you go.

[kevm14]

I need to find out if it has CA emissions or not. If it was originally a CT vehicle, it very well may. Also annoyingly, the cat assembly includes the Y pipe. And the replacement is most likely aluminized. I don't really like any of that. But if I gut the cat, most likely it'll set a cat efficiency code. Maybe I could look into a rear O2 simulator to get around that. Which means I will still have smelly exhaust. SIgh.

Anyway, Walker federal emissions: https://www.rockauto.com/en/moreinfo.ph ... 37&jsn=426
$188.79

Walker CA emissions: https://www.rockauto.com/en/moreinfo.ph ... 37&jsn=429
$279.99

I think I am going to see if I can beat on the cat with a sledge and break it up before I do anything else. For what it's worth, the cat has been rattling for most of the time I've owned it, but slowly worsening. I just thought it was something else in the exhaust. So this all is checking out.