Because i didnt have time and money i was waiting for the pump to just stop working and then i was gonna fix. today one of my friend told me that he can take the car to his highschool and try to find the reason why my car is doing that and he told me they dont charge for finding what causes the problem. i said ok what can i loose so he took it and do couple test with his instructor(my friend told me that he was a race car mechanic and he knows what he is doing).anyway he called me couple minutes ago and told me that his instructor herd that my car was misfiring but it didnt show up on the scan. but he got a code on there fuel lean bank or something like that i think the code was p0117 im not sure about that code but the instructor/mechanic said that its the fuel pressure regulator. i will try to fix that next week or following week and i will let you guys know if it fixed or not.

 

P0117 = Engine Coolant Temperature [ECT] Sensor Circuit Low Voltage

It probably was P0171:
P0171 - Fuel Trim System Lean Bank 1

I'm not too sure I would call this a FPR issue. Even a leaking FPR would typically show more as a misfire on the rear most cylinders of the engine due to the location of the FPR. And the newer engines do not have a track record for FPR leaks internal to the plenum. Typically, they just stop regulating the pressure properly or do not seat properly allowing fuel pressure to leak down after the pump shuts off.

Sounds like you are getting closer to finding the problem though. Let us know how we can help further.

 

Sounds like he thinks its a lean misfire. Check out post #2 again. Print out the link and have the guy look at it. You'll most likely find the problem.

 

It probably was P0171:
P0171 - Fuel Trim System Lean Bank 1....
I talked to my friend again and yes that exactly what it said on the scanner and he did a misfire test on it but he didnt get anything it was working fine when he plug the scanner to the car.My friend told me that there was an other blazer there doing the same problem and he was trying to figure out what was going on. I dont want to take to a mechanic because in this area they like to take people's money and not do anything helpful. For example, when I replace my break rotors and pads. they didnt install it properly and i had problems with them and also the mechanic removed my right emergency break and told me that when i brought the car in it was missing anyway and told me that if i buy the part he would do it for $30. Im sick and tired of their lies. So I read swartlkk's thread but I didn't understand it. Can you explain that to me. Im sorry I dont have much a knowledge about fixing cars. Thank you guys a lot

 

(FPR = fuel pressure regulator)

If the regulator was leaking fuel, you'd get a rich fuel mixture DTC, (diagnostic trouble code) and quite possibly a rich misfire. If fuel pressure is too low, you could expect a lean misfire and lean fuel mixture DTC, like your P0171. First step in driveability diagnosis on these engines is always fuel pressure and leakdown. If the pressure is low or the leakdown is excessive, it doesn't tell you what the problem is, only that a problem exists, and further diagnosis is necessary.

 

So I have a problem with the fuel pressure regulator is that right?

 

Without diagnosis, it's impossible to tell. You need to check fuel pressure and leakdown, then post the results. The FPR on your engine is not a common problem. 1995 and older, yes, but not on 1996 and newer.

 

I took my car to the school again to fix the problem because the teacher was so interested in fixing it. he took it apart to see if the problem was fuel pressure regulator and it was leaking so we are waiting on the part to replace it. I will write the result maybe to night or latest would be tomorrow. thanks for your helps guys

Well I just got the car back I haven't done any fuel pressure test but it starts like new so I will be sure when I do the test

 

hate to hyjack your thread, but my topic seems to be along the same lines and you seem to have gotten some good help.

i have a 2001 blazer 2dr 4.3L V6. been having some fuel pump related problems. 5 out of 6 times it will start up fine. but that other time the fuel pump does not prime the system. no hissing sound when the ignition is on. called a tow truck, and the guy says it is a common problem and if you bang on the bottom of the tank it will start.

sure as **** it does. has been doing it for about a week now. its not a huge issue, but needs to be fixed. is this a need a new pump issue, or something else?

 

If hitting the tank bottom makes it work, then it's probably a bad fuel pump.