Why my truck doesn't pickup speed as it should?

MaraRodz · December 30, 2020

I'm not sure what to say I'm as confused as you are took it to local mechanic today run the scanner no issue make visual check up he drives it than he told me the throttle body might Be failing it didn't throw any code or engine light whatsoever i will need probably to get a second opinion

MaraRodz · December 30, 2020

Can TB fail without showing engine light or codes?

silveradosid · December 30, 2020

i agree with cam, generally anything after the pcm that goes out of spec will trigger the light. but the tps is before the pcm and could be your problem. you need to see if the tps will go to 100 percent when you are in drive. the tb only does what the pcm tells it to do but the tps tells the pcm what to do

MaraRodz · December 30, 2020

Thanks for the reply i will hook the OBD scanner and trun live data and check if the tps will go to 100% if less than that meaning faulty? And i will need to replace a new TB cause i was told you cannot change the sensor you have to purchase a New TB.

MaraRodz · December 30, 2020

Thanks for the reply here's an update i drove the truck earlier and hooked up the scaner according to the live data the TPS when driving goes from 16% to 38% no more than that is that mean need to replace the TB?

truckguy82 · December 30, 2020

On 12/28/2020 at 11:25 PM, Colossus said:

You have a direct injection engine. Even with top tier fuel (which you should always run) and a good fuel additive, you still need to address the carbon build up issue that is common to GDI engines.

Run this stuff in your engine at idle for about 10-15 min prior to changing the oil the next time around. Follow the instructions. This is an internal engine cleaner. Works better and is more efficient than Sea Foam. (Sea Foam is good stuff, but this stuff is 10 times better.)

https://www.bgprod.com/catalog/engine/bg-epr-engine-performance-restoration/

After that, I'd run this from time to time.

https://www.bgprod.com/services/gasoline-fuel-services/gdi-fuelair-induction/

I also run this every other oil change in my GDI vehicles.

https://www.bgprod.com/catalog/engine/bg-moa/

Fuel additives like BG44k which was recently reformulated to better help GDI engines are critical as well. You can run a can of BG44k 2 or 3 times a year if you want, so long as you are using top tier gasoline.

https://www.bgprod.com/catalog/gasoline-fuel-system/bg-44k-fuel-system-cleaner/

Yes, I am a firm believer in the BG products. Amsoil has some good stuff too, but I think BG makes the best additives, followed by Justice Brothers and Amsoil.

Dude, what is this post about. Are you just plugging an ad for BG?

This has absolutely nothing to do with the guys problem and he is listening to your advice, likely because of your post count. You potentially already wasted the poor guys time and money.

CamGTP · December 30, 2020

It's possible that is the cause or something is stopping the blade from opening all the way.

You could remove the air intake and have someone press the pedal all the way to the floor, if the blade doesn't open all the way that would be another way to check it's operation.

MaraRodz · December 30, 2020

I will definitely do that thank you again also regarding the addictive BG product suggested the guys at the Auto zone told me that it have nothing to do with the issue I'm having appreciate the help though

Eddie 70 · December 31, 2020

Sounds like the throttle body is not getting the signal to open to 100% from the actual throttle in the cab. Is there a procedure to get these two in sync. Is there a way to see if the pedal is demanding 100%? We know the throttle body is only opening 38%. To me, something is out of sync. Maybe when you cleaned the throttle body they got out of sync.

MaraRodz · December 31, 2020

Before it was jerking when i drive it but rpm it does fluctuate at that time then i had the throttle body cleaned almost no more jerking but rpm and acceleration stays the same no changes at all.

kickass audio · December 31, 2020

It may have some residue clogging up the throttle body preventing you from opening it up all the way or even something where the gear is broken but not causing a CEL to come up. I had a broken tooth on my Envoy with the throttle body and it was only a problem when driving. I could manually press the throttle body open and close myself and couldn't detect anything with my finger.

I would suggest taking the throttle body off and see if there is a lot of residue on the plate and walls of the throttle body. If it is dirty give it a good cleaning with throttle body cleaner. A useful tip is to grab a old tooth brush with soft plastic bristles and a few q-tips to help in cleaning the throttle body in tight areas.

You can also try to push the throttle body closed and fully open when you have the electrical connection disconnected so it doesn't possibly jam up and break a gear. If it has resistance at certain positions or you hear grinding it could just be with built up residue on the throttle body or a broken throttle body gear set.

I make it a point to clean my throttle body every year from past issues with my Envoy where it was always super filthy. It's cheap insurance IMO.

I also would doubt it would be this but check your mass airflow sensor if it is dirty (I believe the 4.3 has it but I could be wrong, I know for sure the 5.3 and 6.2 have one). That shouldn't change throttle position and limit you as that is based off of torque management but it's worth a quick check.

edit: I think there is a parameter you can see with a basic scan tool for pedal position and throttle body position to see if you have a problem with where the pedal is not seeing anything over ~30% command and the pedal is the culprit. I can't remember the exact parameters for both of those pid's but I believe they are listed for you to look into.

Edited December 31, 2020 by kickass audio

MaraRodz · January 1, 2021

On 12/30/2020 at 5:15 PM, CamGTP said:

It's possible that is the cause or something is stopping the blade from opening all the way.

You could remove the air intake and have someone press the pedal all the way to the floor, if the blade doesn't open all the way that would be another way to check it's operation.

Im sorry to perform this test should the truck be running or not ? I mean i can turn the truck on after i remove the air intake to check if the blade is opening all the way!!