Mechanics

CHEVY LOSE POWER / CHOAKING

1999 Chevrolet Tahoe

Engine Performance problem
1999 Chevy Tahoe V8 Four Wheel Drive Automatic 190000 miles

99 Tahoe - 190k mil. Issue =
For the note its getting worse.

The effects -
Lose of power / Choaking / Baby back fires if I try to put the gas on. I have noticed iv lost major power anyways
from this v8 now then when I bought it (used)

Before (Cold start) No issues. Until the truck worms up after 1 hour? Driving, if I push the gas in to go hard, it has this BAM no power. Nothing. IF I force the gas in even when I know im getting 0 power out of it, (feels like it goes into neutral) it has baby back fires. When I let off the gas, push in 20% it has some what enough power to drive down the street. So when I take off, or even go anywhere, I can not push the gas in much or it will just choke.

Only way I figured out how to fix its self (Before) was
to just shut it off for few minutes. Then I found out I can I shut it off for 5 seconds until computer resets and re start it - (before) I got power and no choking.
But now, even after 2 hours of driving, rebooting (shutting off) does not help 50/50 of the time.
Its getting worse after 2 weeks now?

Prior to this happening, I used to drive only in 3rd.
Then I started to just drive in (D). Started to have check light come on. Then it goes off. Second time it came on got it checked out. O2 Position 1 and 2 censer is bad. Then light goes back off. Only 3 times this has came on, no I haven't changed them.

No, I have not did a tune up, or changed anything.
Not put any fuel cleaner in or nothing.
Avatar
BernieM
March 7, 2009.




Could be fuel pressure related, or TPS(throttl possition sensor) Test like this.
http://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm
Go here and checkout our video.


http://www.2carpros.com/forum/automotive_pictures/62217_TPS_3.jpg


Use a volt meter and check TPS should be smooth, no spikes in voltage and no binding, when was the last tune up?
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Merlin2021
Mar 7, 2009.
N/a fixed

Tiny
BernieM
Mar 8, 2009.
Well with these symtoms it might be the VSS(Vehicle speed sensor) Is the service engine light on? If so go to Autozone, they will read the codes free, post results here.

Merlin2021
Mar 9, 2009.
I figured out the 2wd / 4wd issue.
After hitting bumps in the road and
all that. The darn plug wire was lose.
Took off the dash and pushed hard.
Never had an issue since.

For the Gas / Losing power issue.
No clue yet. With money problems
and time, I have not yet to fix it.
Very soon and when I do ill come back
and update.

Until then, im thinking Fuel pump again,
Or, Fuel Regulator might be it.
The whole choking is making me wonder.

Btw, no light is on. O2 only problem coming up.
Yes, I did get tune up done. Wires,
plugs, fuel filter, cap, rotor 9 yards,
Still no difference.

However.
He did clean my carburetor, that did seam
to help. For 20 minutes =\
Iv bought 5 fuel tank treatments. 4 Carb cleaner and 1 Injector cleaner.

I have also noticed full tank, issue is worse then only having 1/4 tank.

Tiny
BernieM
May 8, 2009.
Test the fuel pump pressure as described above.
Check catalytic converter, may be patially plugged, use a vacuum gauge and bring rpm to 2000, hold steady, if gauge starts to drop from 18-22 hg then exhuast is plugged. If you are having hot weather where you are, it could be fuel related, you could have winter blend fuel and if you run with low fuel tank, it could be causing a cavitation in the fuel pump, (Vapor lock). Keep tank full and test.

Merlin2021
May 9, 2009.
Ok, got it in the shop!
Paid 26$ for them to tell me my Cat*
Is ok. Nothing wrong with it. My fuel (PSI)
Is low. I think 50s? So I replaced my Fuel
filter. Black gunk came out. Still no fix!

Regulator on a 99 Chev Tahoe - No idea
where it is. But what I have seen it was dry.
The uh, Hose was dry. 55$ part I will be replacing
in few days. But still losing power and getting worse!

When I replace the GD fuel pump (250 part + 100)
and if thats what it is I will let everyone know.
And since iv been seeing about how shity this
truck is with the fuel pump issues, im guessing this
is what it is. But in time like this with money,
this will be hard to pay for. But im sure thats what
it is the whole time.

Tiny
BernieM
Jun 6, 2009.
Well low pressure will give you these symtoms, so wont clogged injectors. If any of that black goo made it past your old filter.

Merlin2021
Jun 8, 2009.
Yeah, I went to buy a Fuel pressure regulator.
Went to put it in, but yet I dont have fuel lines.
I found out I have the other type of engine.
SO.

I found out I have to take off the top man/fold
And thats going to take more money.
So.

I hope its just the Fuel pump. And im thinking
it is and it would be cheaper at this point because
from what I hear Fuel pumps go out on these trucks
a lot for some reason.

Tiny
BernieM
Jun 8, 2009.
The other thing you could check is, you said it's fine when cold? If so check the ect(engine coolant temp) sensor, if it's off, it can produce symtoms like this too.

Merlin2021
Jun 9, 2009.
Ok. So my cable went down the day before I fixed
what it was this whole time!

I was correct the whole time!
Fuel pump. FUEL PUMP! OMG! DAM FUEL PUMP!

Ok, I did EVERYTHING to the POS before I changed the
Fuel pump. As the following.

Computer numbers always first.
Cats, Plugs/Wires/cap/rotar, Fuel filter (changed)
Air filter, Idle control Censer, Vacuum lines,
Throttle body censer, Fuel pressure regulator (Changed)
EGR Valve cleaned, Fuel line cleaned, Top Manifold Cleaned,
im sure there is more I did to it. 3-4 months of checking,
Fixing things and all along I knew what it was.
But everyone was trying to stay away from what it was.

After many hours and money. FUEL PUMP!

Symptoms =
Starts up fine, NEVER ever starting issues!
Cold start - Idles fine, Takes off fine, Driving
and it starts to get less pressure = loss of power.
Then it will act like theres no fuel no power, then
as letting off the gas the idle is fine!

I hope this helps anyone else with the issue of the
Chevy (Tahoe) aka POS on this issue.

Tiny
BernieM
Jun 25, 2009.

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