5.7 sluggish under load etc.

brasso · Mar 20, 2017

I've got a 2012 ram 1500 5.7 4x4.

It's started to get extremely sluggish under a load. This includes when in lower gear trying to climb rpms slowly. Oncr it's past 2500 rpms it seems to open up and all power comes back but anything under 2500 it's super sluggish getting there and gas milage has gone to crap. Truck has 117 miles. Any ideas?

I've checked fuel pressure, coils, etc. All has checked out when I really get on it ir throws a cylinder 5 misfire code sometimes.

BrianandChrissy · Mar 20, 2017

There's your answer....you have a coil problem. I would do the plugs while you're in there too.

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brasso · Mar 20, 2017

All coils are fine I checked them. Plugs were just changed less than 20k miles. Those were also rechecked.

Markcuda · Mar 20, 2017

That's pretty low miles for a 2012, like brand spanking new

Burla · Mar 20, 2017

If you got a mis fire pull the plugs on that cylinder and inspect them, scope the hole as well.

Check timing? air filter? fuel filter? check vacuum leaks. clean injectors, run PEA cleaner with good gas?

Rampant · Mar 20, 2017

brasso said:
All coils are fine I checked them. Plugs were just changed less than 20k miles. Those were also rechecked.

I'd run a good injector cleaner through it and change the EGR & PCV valves while you're at it if they haven't been done. Under $100 and a good idea with that many miles anyway. Any and all of those items can definitely cause what you're describing.

Do one at a time if you're really interested in knowing the culprit. If you just want it fixed, do it all at once and be done with it.

Change fuel filter lately? Any starting problems or hesitation? If you do all that and still have the same issues, I'd look for vacuum leaks and then internal valvetrain problems, in that order.

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Burla · Mar 20, 2017

We was probably typing up the posts at the same time, just beat ya Rampant.

Rampant · Mar 20, 2017

Burla said:
We was probably typing up the posts at the same time, just beat ya Rampant.

Haha yup.

Just curious... why would you ask him about checking the timing? It's computer controlled and can't be messed with. True enough, many things can cause it to advance or retard erroneously, but it's very hard to diagnose anything by that.

Did you mean to have him visually inspect the timing chain and tensioner? That seems premature with just over 100k, but I guess it is possible, although very unlikely. That's something I'd only do if I were going to tear into the heads.

He says its only under hard load that it occasionally throws the code. That says air/fuel system delivery to me, especially if plugs and coils are known to be good.

If I were under duress and was forced to guess, I'd say a weak/partially clogged injector #5. The fuel system cleaner will surely make a difference and provide a starting point if a major improvement is noticed.

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Burla · Mar 20, 2017

I was really just brainstorming, that's a good point. I think we agree with everything other then that.

Rampant · Mar 20, 2017

Burla said:
I was really just brainstorming, that's a good point. I think we agree with everything other then that.

I'm with ya 100%.

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brasso · Mar 20, 2017

This truck does not have a fuel filter. Just a sump sock at bottom of tank. Coils and plugs are good. EGR valve? On a 12 hemi?

huntergreen · Mar 20, 2017

Faulty valve seat or injector.

Rampant · Mar 20, 2017

brasso said:
This truck does not have a fuel filter. Just a sump sock at bottom of tank. Coils and plugs are good. EGR valve? On a 12 hemi?

Holy wow, I was wayyy wrong! Didn't know they went away from them in '12. The last 5.7 I had was in '06. I'd still concentrate on the fuel system and vacuum leaks before anything else.

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RLJ10X · Mar 21, 2017

My guess is as worthless as everybody elce's, because it could be a number of different things.

If it was me, l would run Fuel lnjector cleaner thru it for a while. I've had surprisingly good luck with that stuff.

If that didn't do it, l would bite the bullet, and take it to the dealer, if you have a good one close by.

brasso · Mar 21, 2017

Thanks guys. I've ran about 4 tanks with lucas in it so far with no luck. What scares me is I've had several tell me they had same issues and it was a rounded cam.

Burla · Mar 21, 2017

Lucas is not a fuel injector cleaner, it is a UCL, Upper Cylinder Lube. You need a PEA cleaner, Redline S1 or Amsoil fuel cleaner have the highest % PEA. Pair that with a high detergent gas like chevron or Shell, best bet. I use Lucal and MMO still have a gallon of each in the garage, they don't clean for nothing, just make your engines whatever they are run a lil smoother. If your injectors are shooting a stream instead of a mist, you will get a serious lack in performance.

Rampant · Mar 21, 2017

Burla said:
Lucas is not a fuel injector cleaner, it is a UCL, Upper Cylinder Lube. You need a PEA cleaner, Redline S1 or Amsoil fuel cleaner have the highest % PEA. Pair that with a high detergent gas like chevron or Shell, best bet. I use Lucal and MMO still have a gallon of each in the garage, they don't clean for nothing, just make your engines whatever they are run a lil smoother. If your injectors are shooting a stream instead of a mist, you will get a serious lack in performance.

What he said x2

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RLJ10X · Mar 22, 2017

I just ordered a bottle of S1. So, Burla, if this stuff isn't noticeably better than Lucas, you're in big trouble, Buddy!

Brassiere, look at the bright side, you now have a good excuse to get a performance cam from Moe's.

Burla · Mar 22, 2017

Most of the top ten fuel cleaners are PEA cleaners, top 3 are all PEA cleaners, none of them are Lucas UCL or MMO. Gives me a little hope that the consumer base actually does a little research. I buy Redline by the case, less then 10 bucks each when you do from ebay. Of the top 3, Techron has been sketchy with their formulation of PEA and charges a fortune, RP has 5 to 15% PEA, and Redline has 25% plus for the same price. Amsoil not in the top ten has the highest % PEA, but is less ounces then redline. I would have to say either would be the best choice until and if someone comes around and makes a different formula.

Google PEA cleaners and look at the posts at Bob's, over there if you don't have PEA in your formula, there is zero interest in the product as an injector cleaner.

brasso · Mar 23, 2017

Guys, put injector cleaner in tonight and will report back.

The truck still has wierd symptoms. It seems as if Ive got a giant rubber band holding me back when it's around 2000 rpms. Once it gets to 2500 it seems to gain power back. It's almost as if something is blocking it from getting full power around 2000 rpms. I can punch it and it seems to do just fine but when I gradually climb rpms without making is drop a gear or two its super sluggish and almost feels like it's running into a ton of wind especially around 2k rpms. Once im cruising and it's at around 2k rpms its as if something is holding it back. Once it climbs and gets to about 2500 rpms or so it's like it gains power and begins to start really going. It had major issues pulling a light duck boat as well. Got 8mpg

5.7 sluggish under load etc.

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