2004 2500HD gas reduced engine power?

[nickc]

some of the trucks have a throttle cable. it sounds to me like your rig has an electric throttle body. if that is the case clean the carbon off the inside of the throttle plate with a soft tooth brush & throttle cleaner. not carb cleaner !! seen it many times. good luck

 

[calhoun9001]

GM has a kit now so you don't have to change the hole throttle body. It comes with just the sensors that attach to the side of the throttle body. Pretty easy to change. Put them on all the time for throttle body codes. Any time the sensors in the throttle body don't match, you end up with reduced engine power.

 

[kham0315]

I dont think the cover kit works on these earlier trucks. I think the cover is riveted on a 2004 unfortunatley. Definetely need to clean throttle plate like nickc suggested. should be done atleast every 30k.

 

[RPW]

Had the same truck and same problem. It most likely is in the wiring harness at the throttle body. Mine never really went away but I'd do the cleaning anyway as that is an issue also. Keep in mind that although a fairly easy procedure there are some gotchas.

Good luck.

 

[lostcause]

I had a similar problem with a slightly older truck (2000 gm with a 5.7) though my issue was usually more noticeable when towing rather than empty, but it was intermittent. That truck didn't have the onboard diagnostics that the newer ones do, so troubleshooting was more difficult. To make a long story short, after a lot of test drives a factory dealership was finally able to reproduce the problem, but there were no codes to make an easy diagnosis. after a few calls to a GM tech line, one of the techs asked if it has a K&N filter on it - it did. What happened was that tiny oil particles would pass through and adhere to the mass airflow sensor. They would obscure the sensor slightly, causing it to make faulty readings and improperly adjust. I had bought the truck 2 years old, and the filter was already installed, and I have no clue if this is an often occurring issue, or whether it had been previously over-oiled. Since the GM tech line was able to guess at it without seeing it, it tells me that it must have happened before too.

I'm sure that this isn't your issue, but it's something to keep in mind.

 

[tylertown]

I had a similar problem with a slightly older truck (2000 gm with a 5.7) though my issue was usually more noticeable when towing rather than empty, but it was intermittent. That truck didn't have the onboard diagnostics that the newer ones do, so troubleshooting was more difficult. To make a long story short, after a lot of test drives a factory dealership was finally able to reproduce the problem, but there were no codes to make an easy diagnosis. after a few calls to a GM tech line, one of the techs asked if it has a K&N filter on it - it did. What happened was that tiny oil particles would pass through and adhere to the mass airflow sensor. They would obscure the sensor slightly, causing it to make faulty readings and improperly adjust. I had bought the truck 2 years old, and the filter was already installed, and I have no clue if this is an often occurring issue, or whether it had been previously over-oiled. Since the GM tech line was able to guess at it without seeing it, it tells me that it must have happened before too.

I'm sure that this isn't your issue, but it's something to keep in mind.

mine has the k&n intake system on it from a previous owner! and I did happen to re oil the filter and clean it about 500 to a 1000 miles before this problem started! thanks im going to clean every thing this evening and that could really be the problem. because my reduced engine power is getting more and more constant. now down to a mile or two before it throws the code at me.

I could have over oiled it and its causing stress on the actuator motor. going to do that first before I start spending money. im not a fan of k&n but since it had one I didn't pay it any attention but I bet that is the problem. thanks for the info I will let you know how it goes as soon as possible.

Thanks guys!

 

[lostcause]

mine has the k&n intake system on it from a previous owner! and I did happen to re oil the filter and clean it about 500 to a 1000 miles before this problem started! thanks im going to clean every thing this evening and that could really be the problem. because my reduced engine power is getting more and more constant. now down to a mile or two before it throws the code at me.

I could have over oiled it and its causing stress on the actuator motor. going to do that first before I start spending money. im not a fan of k&n but since it had one I didn't pay it any attention but I bet that is the problem. thanks for the info I will let you know how it goes as soon as possible.

Thanks guys!

it's been over a decade since i had this issue, so i can't remember the exact cleaning process they did, but i think it was just to wash the mass airflow sensor with carb & choke cleaner. i wouldn't take that to the bank though. i'd ask a pro whether that is an acceptable solvent to clean it with, or whether there is something else you should use.

i've got a 2006 now with the 6.0 - i assume it's pretty much the same as you have, but i decided after that one to leave the stock filter element on. don't get me wrong, i've used k&n filters on quads that got so muddy & wet that they wouldn't even get me home on a dried out normal filter and they were flawless in all conditions on the k&n. it's just that one bad experience on this made me real cautious about using them on anything that is self adjusting.

 

[nc redneck]

Had the same truck with same problems. Went to researching online replaced K&N with paper filter, never had a problem again.

 

[mikehaugen]

They make a specific "mass airflow sensor cleaner" available at most auto parts. Do not use carb and choke cleaner.

 

[tylertown]

They make a specific "mass airflow sensor cleaner" available at most auto parts. Do not use carb and choke cleaner.

thanks mike I used that throttle body cleaner solution they sell at advance auto and cleaned it the best I could without moving the valve with a tooth brush the electric motor itself was riveted to the side of the throttle body so I didn't try to remove and do anything to it. I drove it home from the shop tonight and no problems yet I will know by the end of the day tomorrow. it messed up on me 6 times today but early in the morning. it was cold but its colder tonight and no problems so far.

hope it works because the way things look on the throttle body they sell it as a whole piece with the motor attached witch im sure is going to be fairly expensive.