Engine Turning Over

Hi I drive a 03 tacoma doublecab and recently replaced the head gasket cover, and fuel filter. After I noticed that the engine wont start up when turning the key the first time. It'll turn over a bit then I'll stop try it again and usually the second or third time it'll fire up. When I turn on the car I can hear the fuel pump prime and I'll give it about 5-10 seconds before trying to start engine, but with that it still turns over. I'll pump the gas pedal for the second/third time I turn the key and that usually gets the engine going. I'm guessing a faulty fuel pump? I'm no expert but it sounds like either not enough fuel is getting pumped on start up or that the mixture of air/gas/spark is off. There's also no lag when driving or anything, and once running, the engine purrs. I also noticed that when I unscrew the gas cap I hear a hissing sound almost as if the fuel tank was pressurized. I've never ran into anything like this, maybe that hints as to what could be problem.

Also should I avoid driving the truck while I have this problem. Could this lead to damaging the engine down the road?

 

Not sure what you are hearing but the fuel pump on these trucks does not start when the ignition key is turned to the "ON" position. The fuel pump starts when you engage the starter and the engine begins to crank over.

Pumping the gas pedal is something we did with carburetors, not electronic ignitions with fuel injectors.

The hissing you hear when you open the gas cap is normal.

 

Fuel pump relay, maybe.

 

Does the pump not prime?

Understood, so then could it be a problem with fuel pressure regulator? And thats why pumping the pedal helps the engine start up? Also I forgot to mention I recently got the fuel injectors cleaned.

 

Not sure what you mean with this statement..Are you meaning to say the valve cover gaskets? Like the others have stated don't pump the gas pedal on these trucks, it's not needed. Have you tried running a code reader to see if its throwing any codes?