Vortec 8.1 hesitating on acceleration and under load

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Question: when it starts "Acting up" do you get a Check Engine light that then goes out?

If so get a OBD-II to"Radio" adapter.. i will describe two types.

I have T-mobile "Sync up and go" on my car. it talks to the same name app on my phone via both Wi_Fi and Cellular  Not that happy with it fort there is no easy way to "Talk back" to the Engine control computer. but if there is a "Soft" code (one that goes away when you re-start) it will be logged.

I also have a OBD-II to Blue Tooth that talks to the TORQUE app on my phone, in fact they "Chat" which is to say I can RESET codes from the phone.

Again it logs.
 
I have a ScanGuage 2 always plugged in. But, no codes.

And the spark plug wires were replaced last year, and I think they were Delco. So, it would be odd to have a wire go out, but still possible I guess.

Could the heat here cause issues? Never had this issue back east.
 
Question: Could this be a gasket issue on the exhaust, considering it isn?t making any loud noises? The only time I?ve had this happen before, it was a blown exhaust donut gasket. Felt pretty similar. However, the thing sounded like a lawn mower so it was fairly obvious. :) Not this time. But it feels similar, with lower compression.

Just spitballing. :)
 
I dont think your problem is the exhaust gasket (doughnut) you could always check it, see if any black soot is around the fitting.

I would go back to the fuel delivery issue, you stated that the pressure was still a little low after putting a new fuel filter on.  What was the reading?

Fuel pressure should be 58-64 psi. 

You can get a fuel pressure gauge from autozone/oriellys one that will attatch to the schrader valve on the fuel rail, check it before you change out the filter, then change out the filter and check it again.

If the pressure is still low, then your going to need a new fuel pump, and the tank will have to be dropped.

You can get the following gauge at AZ, you dont have to buy it, when you return it you can get a refund  (loan a tool)
 
    Just a suggestion on spark plug wires, I have had consistently favorable performance from MSD like the ones in the link. I get the universal set and make the up so I can route them away from headers and hot exhaust pipes.  Anything less than these have given trouble. OEM parts are quality but in my humble opinion these are better....just my two cents...

https://www.summitracing.com/search/brand/msd-ignition/make/chevrolet/engine-size/8-1l-496/section/spark-plug-wires-and-accessories
 
John From Detroit said:
I also have a OBD-II to Blue Tooth that talks to the TORQUE app on my phone, in fact they "Chat" which is to say I can RESET codes from the phone.

Again it logs.
Click to expand...

John, just a quick side question.  I've seen the Torque app mentioned in a couple of threads recently.  Did you pay for the full app? And, if so, was it worth the upgrade from the free app?

Yeah, okay, so I'm a little cheap.  I downloaded the free version and I like it better than the one I've been using, but am unsure if the full app adds enough to make it worth the upgrade.
 
Old_Crow said:
John, just a quick side question.  I've seen the Torque app mentioned in a couple of threads recently.  Did you pay for the full app? And, if so, was it worth the upgrade from the free app?

Yeah, okay, so I'm a little cheap.  I downloaded the free version and I like it better than the one I've been using, but am unsure if the full app adds enough to make it worth the upgrade.
Click to expand...

We're also using the free version and would like any info on the upgrade. 
 
We've moved on into California. The problem is still occurring, but the land is flatter and I've gotten pretty good at managing the transmission, so it's been fairly smooth. But, 2-3 times on the 267 mile trip here from Vegas, I could feel it hesitate up the hills. Few other observations, if it helps anybody give their ideas...

One thing I've noticed, though, is that even if you don't feel the vehicle hesitate, it still seems to take more throttle than it should to climb hills that, in the past, wouldn't have been much of an issue.

Oddly, tho, we put gas in it yesterday and I calculated MPG... and it's about right on average. So, it isn't taking much more gas than typical.

I do feel the engine should have more umpf than this.

It really feels like I'm chasing a ghost here. :) The problem is there, but it only rears up occasionally and otherwise the engine seems to be running smooth as silk.
 
go to the auto parts store buy a set of cheap wires and change out 7 and 8 wires. Get the engine warm and pull some grades. Problem gone then get some GOOD wires. Problem stays then put old wires back and search elsewhere for your problem.
You can buy individual performance wires for about $10.00 each so for 20 bucks and 1/2 hour time you will find out.
 
May do that. I am carrying a set of NAPA wires with me in case I elect to try a change out.

Up above, Gary said damaged wires aren't too common on the Vortec. I've seen others say differently, but many others say it happens. As I said, I put on new wires last year as part of a tune-up and it made a great difference in how the engine ran. The wires they put on there were not Delco's, though. They were a set of Beldins from NAPA so that's what's on there now.

But, changing out a few wires would be quick and easy, and I am carrying a set with me. So, perhaps I can give it a whirl.
 
Old_Crow said:
John, just a quick side question.  I've seen the Torque app mentioned in a couple of threads recently.  Did you pay for the full app? And, if so, was it worth the upgrade from the free app?

Yeah, okay, so I'm a little cheap.  I downloaded the free version and I like it better than the one I've been using, but am unsure if the full app adds enough to make it worth the upgrade.
Click to expand...

I did. but more for other reasons. I did not gain much and lost a thing or two.  I would suggest you go with the FREE version first.  The app is a bit limited by the vehicle control computer. IT can not read sensors that do not exist :).
 
http://budeberwein.com/ 

This is the the Workhorse dealer in Fresno. I've been going there 10 years.

Call and ask for Zarkas, he's the owner and usually answers the phone.

Tell him Arch sent you.  They are honest and use all Workhorse parts. 
 
John From Detroit said:
I did. but more for other reasons. I did not gain much and lost a thing or two.  I would suggest you go with the FREE version first.  The app is a bit limited by the vehicle control computer. IT can not read sensors that do not exist :).
Click to expand...

Yeah, I downloaded the free version and played with it a bit.  Took me about 2 minutes to realize I like it better than the Russian app I'd been using(didn't realize it was Russian until I pulled up the "help" menu and it was in Cyrillic).
Of course, now I'm at a hosting job until Nov, so I won't really be able to play with it for several months.  Looking forward to seeing how much boost I can get on this V-10  ;D
 
Update:

Noticed a couple times now that the engine is a bit sluggish starting up. Seems like a fuel issue. Would a messed up fuel pressure regulator possibly explain all this? And, easy to replace for a non-mechanic? :p
 
Actually, pulled vacuum line off regulator and saw no fuel. Looks dry. So does that mean it isn?t the fuel pressure regulator?
 
drisley said:
Actually, pulled vacuum line off regulator and saw no fuel. Looks dry. So does that mean it isn?t the fuel pressure regulator?
Click to expand...
I realize this is a very old post, but if possible I would like to learn the outcome of this issue as I am currently experiencing the exact same symptoms and have been unable to find a solution. I too am out west from Florida and don't know if I can continue to get home to my mechanic or will it continue to worsen and eventually leave me on the side of the road. Thanks for any help.
 
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