Pinging at about 55mph in 5th

[Dep. Ranger]

I have had this problem with my truck for at least a year now. I finally have some time to try and fix this lingering problem. When I am driving on the highway at about 55mph, my engine starts to ping. I don't think it is a miss, because there is no jerk or stumble to the engine. Also at 55mph trying to accelerate is rather difficult for my truck. I have been reading postings about these issues. I have recently installed new plugs, wires, battery, and an alternator. I am getting about 18mpg so I don't think this is effecting my mpg.

So I guess what I am asking is what could be causing my engine to ping in 5th gear with low rpm?

 

[Dep. Ranger]

Thanks for the advice. so if i am driving on a highway at 70mph what gear would you recommend? i have no tachometer so i dont know the rpms. I use the lowest grade, i think it is 85. Also what is the IAC (intake plenum) and where is it located?

 

[martin]

5th gear is really just for cruising and should be good even at 55 but if you are fighting a head-wind, going up hill or accelerating you should shift down at least one gear. don't be afraid to rev the 3, it's quite happy in the upper rev band.

 

[Hahnsb2]

Driving 55 on the hwy in 5th on a 3L is very bad, your lugging the engine and that will cause a carbon build up inside the plenum, IAC and cause pinging. From now on use 4th when your doing 55 on the hwy.

Anyhow check the IAC, intake plenum for any carbon build ups. Check the mass airflow sensor to see if it's dirty. What kind of gas are you using?

I agree, he's likely lugging it.

Seafoam it and don't be afraid to rev the piss out of it and it'll likely go away...

 

[Dep. Ranger]

Martin, Why do you say that the 3.0 is quite happy in the upper rev band?

 

[Dep. Ranger]

Hahnsb2, what would be the benefit of using sea foam? my engine is only at 87,000mi.

 

[pcollins]

i use 5th gear at anything 55mph or above. not sure if the 3.0L is different speed wise from my 4.0L. but i can tell you 5th gear is certainly not luggin my engine. at 55mph, in 5th gear in my truck, the engine is at 2000rpm.

 

[Dep. Ranger]

Thanks for all the info. I am glad I finally brought this up. Would you guys recommend filling it up with mid-grade gas and adding some octane booster? Any other solutions besides sea foam. I just installed new plugs and I am kinda worried about the potential bad outcomes of sea foam. Thanks again for all of yalls help.

 

[Dep. Ranger]

Thanks mtnrgr for the quick responses i will definately do that. do you recommend any specific brand of fuel cleaners?

 

[45acp]

i'm the other guy posting about this problem

Yea, same exact problem & I posted what i've done & what it accomplished. I did forget to post though that when I switched to premium 93 octane gas, it felt like I gained 30 horsepower! Now that just ain't right. something is reading that octane wrong or responding to it wrong. (still kicking myself in the ass for selling my 4.0 /5sp)

 

[Bigschwerm]

Carbon build up can cause pre detonation by creating hot spots in the cylinder... Now by running 93 octane will help with the pre detonation (the higher the octane rating of the fuel the more of a controlled burn it is)

http://en.wikipedia.org/wiki/Octane_rating

 

[Froggmann]

If your truck is Flex Fuel, run E-85 through it. It puts any off the shelf injector cleaner and carbon cleaner to shame. Trust me.