Very slow to accelerate from a complete stop

JBALES3311

MEMBER
2008 CHEVROLET TRAILBLAZER
6.0L
V8
2WD
184,112 MILES

When I take off from a complete stop it is very slow to pick up speed but once you get going it starts to speed up. But at 60 mph the rpm's are at about 2,700 rpm's the truck is automatic so I tried shifting it all the way to first and manually shifted it first-fourth it takes off way better but still sluggish. I noticed today after driving for awhile when I parked the truck an let it idle the oil pressure went to 0 but when driving the oil pressure it dead center between the half mark an hot (in the red all the way to the right) I don't think fuel problem but I'm not a mechanic. Can anyone help?

6 Replies

MEL GARRISON

MEMBER
4 POSTS

Trailblazers of those years the oil pressure sensor doesn’t really read exact pressure if it’s above a certain point it will read 40 or like 60 and if it gets down to a certain point it will drop to zero. Most of the time it’s a sensor on passenger side of engine on top right above power steering fill. It’s a oil sensors that has screens and controls oil flow and the screens can get clogged or it can just go bad. Or it could just be the oil pressure sensor itself they go out on those engines too. Buy a cheap odb 2 reader and will usually tell you if it’s one of those problems. Or go to like auto part store most of them will check your odb 2 for free.

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Sunday, July 14th, 2019 AT 3:41 AM

JBALES3311

MEMBER
3 POSTS

Okay, I'm going to do that this morning. Do you think that is what is causing the sluggish acceleration? And thank you.

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Sunday, July 14th, 2019 AT 5:41 AM

STEVE W.

MECHANIC
13,476 POSTS

When it accelerates what do the rpms do? Revs higher and the truck slowly picks up speed? Slowly go up as the truck gains speed? If you rev it in neutral what does it do? When was the last time the oil/filter and air filter was changed and is it full of oil? When was the last time the transmission was serviced? Does the exhaust sound different, like a hiss or whistle? Could you shoot a video of it so we can see and hear what it is doing?

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Sunday, July 14th, 2019 AT 7:18 PM

KEN L

MASTER CERTIFIED MECHANIC
47,686 POSTS

This sounds like you could have a plugged catalytic converter. To be sure here are to guides that will help us fix the problem:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

and

https://www.2carpros.com/articles/engine-has-low-power-output

Please run down these guides and report back.

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Monday, July 15th, 2019 AT 11:34 AM

JBALES3311

MEMBER
3 POSTS

The rpm's gradually increase as you accelerate, if I rev it in neutral it's normal, I have figure out its not shifting into fourth gear but when accelerate on the highway doing about 60 mph it's at 2800 rpm's an when I let off the gas the rpm's drop back down to 1,400 or so (normal)it coasts instead of bogging down an rpm's shooting up, it had a oil change 18 days ago an I checked transmission fluid it was good. The exhaust doesn't sound different but when you sit still at a red light or something and it is just idling it shakes but as soon as you try to accelerate it stops but still no power. I don't have extra cash to put it in the shop we just lost our home in a fire it is my only way to work. I remodel houses so I'm going to have to fix myself. I will post progress on suggestions y'all have and I will take a video in the morning of how it accelerates an runs. Thank you really.