My truck has a few people scratching their heads. It's an 06 QC short bed 2wd 4.7 with roughly 230k miles. Anyways, I am having a power issue with my truck and not sure what to check next. Right after I bought it I put in a K&N stock replacement filter in it to help out. It already had an off brand dual exhaust. Other than that the motor is stock (to my knowledge). I have stock 20s with factory sized all terrains and a leveling kit. I've noticed over about the past year ish the power in the truck has been declining. Fuel pressure runs 61psi and never did below 60. I replaced spark plugs with I believe champion iridium's with no avail. I've sea foamed the tank numerous occasions and did the throttle body a couple times as well as vacuum once. I only run 89 or 91 octane in it. Runs best on QuikTrip gas. When it runs straight gas it will buck a little, randomly but normally holding speed. Under any kind of load like climbing a long overpass on the freeway I'll lose about 5mph. I've cleaned the map sensor and made it better for a couple days. I've done quite a bit to get it better, and when it does run right it's only for a couple days. No CELs. Anyone have an idea what to check? Thanks in advance.

 

Yup. It’s a 4.7 in a 5000 pound truck. Mines been doing the same thing it’s whole life. Programmers, intake, gearing will help with that problem but it’s never going to be a race truck

 

It's understandable with it only having 235 hp but even with just my wife and I we have a hard time going up hills. But there has been a couple times where it's great and won't lose any speed whatsoever. Mid-range seems good, but low end definitely struggles as well as the high to end. Somewhat ruling out injectors as I have no CEL. Doing compression check tomorrow.

 

Get rid of the iridium plugs. These trucks simply don't care for them. Standard copper plugs only please.

 

Definitely go with the coppers. While you're removing plugs, consider doing a compression check.

 

+1 on the copper plugs.

 

Is the tranny weak/ low fluid? You may have 61 psi at fuel rail but that’s not the injectors, could have plugged injectors with that mileage, cat could be getting clogged/ broken apart. Could have low compression, stuck valve…..time to start digging

 

Something is wrong though. Never gonna be a race truck but should make it up hills, no problem. Admittedly, I've got a lighter 03' Dakota, but this things got 326K mi on it and it's a quad cab, which ain't exactly light and it pulls very well. Furthermore I've towed cars on heavy trailers for hundreds of miles, rear end squatted down to almost rubbing the tires (one trip was almost a thousand) and barely felt them back there. Could be a vacuum issue, wrong plugs, low fuel pressure etc. Also, when you buy a used vehicle you buy someone's maintenance history, good or bad. Eg: Truck could have been run low on oil for an extended period. I'd run a cylinder compression test and see if any cylinders are out of spec. I scoped mine years ago and saw hatch marks still there. I was around 275K then.

 

Sorry it's been a while since I've been on. Given the pressure reading is at the fuel rail which is directly connected to injectors... , But anyways I'm not fully ruling out a transmission issue. I know the truck, in it's previous life, was a work truck and person probably didn't understand the concept of tow/haul mode. It just started leaking from tail so it could be a typical dodge transmission. Also I've heard the 545 with 4.7 isn't exactly ideal for towing with the Rams due to it being heavier and needing to be in higher RPMS for towing up hills. I'm also not ruling out cats. I know they have been replaced before, but don't know brand, when, etc. I am leaning more towards injectors for now due to it running better with fuel treatment. And if not then I have a new set of injectors.