Mechanics

CHEVY ENGINE STALLING WHEN ACCELERATED

1998 Chevrolet Cheyenne

Engine Mechanical problem
1998 Chevy Cheyenne V8 Four Wheel Drive Automatic 94000 miles

Engine is stalling when accelerated. It idles fine and if your cruising at a steady speed its fine until I accelerate and it gets worse as the engine gets warmed up. And its getting worse by the day. I changed the fuel filter and the air filter is clean. When it starts to stall it sounds like it's backfiring through the carburetor. Could you let me know what you think could be the cause of this? Thanks:
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Smiling cro
March 9, 2008.



Does this motor have a carburetor or a throttle body? Carburetors are not stock on these engines. Pull all the plugs and tell me what they look like.
Is this motor fuel injected? Is it a Vortec? Does the exhaust seem to be restricted?

Tiny
Pear69
Mar 9, 2008.
These trucks have a few common problems. First of which is the coil wire grounding out on the transmission dipstick tube. Second is a weak volume from fuel pump, to test this you will need a dc amp meter(you can purchase one for about ten bucks) with meter on dc amp 10amp scale put one side to positive side of battery and the other side to the fuel pump test lead(this is either on passengers side by firewall, it will be a single wire with a pig tail at the end usually red or gray colored wire, or its located at the drivers side at the under hood junction block you will see the pig tail) you should have at least 9 amps minimum(were ideally looking for 10 amps. Not overlooking the obvious when was the last time she was tuned with new wires and cap and rotor? Get back to us.

Tiny
Mastertechtim
Mar 10, 2008.
The motor is all original and it is a 5.0 vortec fuel injected throttle body. The motor has never been tuned up. But the manifold intake gasket was just replaced 2 weeks ago and the fuel pump was replaced 4 months ago. Please let me know if you think of any thing else meanwhile Ill pull the plugs and run a meter on the fuel pump.

Tiny
Smiling cro
Mar 10, 2008.
I would definitely start with a complete tune up, it needs it. Bottom line is I think your going to find that you need a tune up and or fuel pump. Let us know

Tiny
Mastertechtim
Mar 10, 2008.
I agree, a tune up cannot hurt. Be sure to use A/C Delco plugs and wires. Do not make the mistake and put any other brand plug or wire on this engine.
Another common problem with this engine is the fuel pressure regulator and clogged up injectors.

Tiny
Pear69
Mar 10, 2008.
What is the fuel pressure regulator and where is it located? Can it be changed fairly easily?

Tiny
Smiling cro
Mar 11, 2008.
Had auto zone run a check and it came up with a OEM number to cross: P0452 and said FUEL TANK PRESSURE SENSOR CONDITION. Do you think the fuel pressure regulator could be the cause of this. It also showed Probable causes 1-FUEL TANK PRESSURE SENSOR DEFECTIVE. 2-CHECKCONNECTOR AND WIRING. &Amp; 3-CHECK HOSES AND FITTINGS. Please let me know what y'all think. And thanks for all the help so fore. By the way I changed the plugs, wires, cap, & rotor it definitly needed it but it is still stalling once it warms up and only when I exelerate. Thanks again.

Tiny
Smiling cro
Mar 12, 2008.
The tank pressure sensor is located on top of the fuel pump assembaly. Right next to where the fuel pump electrical connector plugs in. There is a three wire connector for the sensor. You have to drop the tank to get to this sensor. P0452can also be a bad gas cap--believe it or not. Try changing the cap first.
The pressure regulator is located under the UPPER intake manifold and connects to the fuel bowl (where all of the injectors are). You must remove the plastic intake cover to access it.

Tiny
Pear69
Mar 12, 2008.
Smilincro I think werre onto something here. I remember back in the days at the dealership I had a blazer intermittently dying while driving and what it ended up being is the fuel tank pressure sensor. I agree these are not common to go bad and a loose gas cap most often causes this code. If the sensor is actually bad it will bring down the map sensor voltage because it shares the same 5 volt reference. Hence causing a severe hesitation. You can check it for sure with a scanner and with the gas cap open it should read about 5 volts. If it reads below 4 volts then thats your hesitation

Tiny
Mastertechtim
Mar 12, 2008.