Nearly every modern fuel-injected car and truck requires a fuel sending unit. The Fuel Pump for 1999 to 2003 Chevrolet and GMC Pickup Trucks takes the form of an electric pump mounted in the fuel tank, which you might be able to hear as a quiet whirring sound when the key is first turned. This pump doesn't just send gas from the tank to the engine but it is also maintains the required pressure within the fuel system to ensure the injectors deliver the correct amount of fuel into each cylinder so the engine can deliver the performance you need. But when your electric fuel pump has issues it can cause major drivability problems for your car.
One of the first indications of a bad electric fuel pump is when the normally quiet hum becomes noticeably loud and impossible to tune out. This noise usually means the bearings inside the unit are failing and the rotating part of the electric motor is starting to grind. Unfortunately, this means the entire fuel pump sending unit needs to be replaced since the bearings aren't serviceable and because added wear and tear of the grinding will eventually cause a complete failure down the road. When your fuel pump is loud, you have a little bit of time to fix it before the problem gets bigger.
Trouble getting your Silverado, S-10, Sierra, or Jimmy started after a fill up or after the car has been sitting for a while is another sign of a faulty fuel pump. A fuel pump is always on when the car is running and on a car or truck with a lot of miles, the fuel pump could be worn out and weak. The residual pressure in the fuel lines diminishes as a car sits and every time you open the gas cap and a weak fuel pump will often take more than turn of the key to build the fuel pressure up to a point where the vehicle can run smoothly. And if the fuel pump has failed entirely, you may not be able to start the car at all, leaving you stranded.
An intermittent problem with the electric fuel pump can also decrease the performance of your Chevy or GMC's 4.3L, 4.8L, 5.3L, or 6.0L engine and cause rough running. Without the proper mix of fuel being supplied to the engine, the air/fuel ratio becomes lean which can cause a loss of power and slower acceleration. It can even cause misfires or make your engine stall if the pressure or volume of gas is low enough.
On many GM vehicles, including the Chevy Silverado, GMC Sierra, Chevy S-10 Blazer, and the GMC Jimmy the fuel pump assembly also houses the fuel level sender. So if the fuel gauge on your dash has been acting erratically or never showing full, it could be a problem with the fuel pump sender unit even if your car or truck runs fine. On vehicles with an integrated sender and fuel pump, you'll need to replace the entire unit to get an accurate fuel level reading.
If you've started to notice any of these symptoms and you drive a high-mileage vehicle, it's very likely you'll need a replacement electric fuel pump for your Chevy or GMC Truck soon to keep it on the road. At BuyAutoParts.com, we stock a huge range of guaranteed exact fit replacement electric fuel pumps for the S-10 Blazer and GMC Jimmy as well as fuel sending units for the Chevy Silverado and GMC Sierra. Before you make the repair yourself, be sure to have less than quarter of a tank of gas before you open the access panel to the pump assembly and keep a rag handy and over the fuel lines as you disconnect them to keep any pressurized fuel from spraying all over.