i have 2001 2dr 2wd vin w,auto trans, and have serious problems, but it is intermitten, it starts fine, runs fine until it is drove for an hour or so, then it starts acting up, first acts like it is being held back, like its the converter, which i replace the other day but it still does it, after the period of being held back with no power, it starts bogging down first at more aggresive throttle, but gradualy gets worse, all the way to the point of bogging when you barley touch the petal, then it will stall, and pick back up when you let off the gas, but if you cut it off, it will run fine for a min or two, then does this all over again, but sometimes i can come to a stop when its doing this, and it will stall, but when it is restarted it runs good for a few minutes and its the same thing all over again, it also intermittenly has starting problems, about once every few days, i can stop at the store and then get in it to go and it wont crank, like it has no fuel, it will sputter every now and then but nothing, it will start after about 10-15 mins of messing with it, you have to do nothing except keep trying to crank it, and it seems like every time, right when your about to give up, and you give it one last crank, it starts right up, also sometimes when this problem with the engine bogging down happens, it will catch and it will rev, but acts like the tranny is slipping, its really weird, and i am at a loss, i really need some help, also you can smell fuel, and the plugs almost look like they have tried bridging, and the gap has to be 80 or more, im not sure what is causing all this, but the plugs are also grayish white, also my fuel pressure is 60 on key turn and a steady 55 running, i havent been able to check the fuel pressure when it acts up, it is 2001 sls 2 dr 2wd vin w

 

Does the check engine light come on and then off when you turn the ignition on?
Does the check engine light come on or flash while driving?
Have you had the codes retrieved?
If so, what are they, and what order were they retrieved?
Fuel pressure: Ignition in the RUN position, (don't start the engine) fuel pump running: Pressure must be 60psi to 66psi while the pump is running. Fuel pressure must remain above 55psi for at least 10 minutes after the pump shuts off. Post your results.

 

check your fuel pressure again with the car running, and then while you are looking at the gauge, smash the gas. it will probably drop below the minimum value and then you will know that you need a fuel pump. the bogging and everything sounds like what my 95 did back in the day. it would run really good at part, rolled on, throttle. but when you needed to get out of the way of something, it would bog real bad and almost die.

EDIT: next time, try and break things up in your post. some times for some people its hard to read because its so long. and make sure that you are hitting the right key on the keyboard, there are a whole bunch of commas, and no periods. just saying.

 

i have had several codes, but all but 2 were abs related, something to do with the right front wheel speed sensor, but other codes were o2 sensor, and was apperently on because a sensor wasnt hooked up, i hooked it back up, the other code was a random misfire code, and a code that said incorrect security passcode, but fuel psi, 60 key on pump running, started engine running, stays 55 psi steady, but when you gun the throttle, it drops a few, like maybe to 48-50 psi, but comes right back up, i havent been able to check it when its acting up yet only on a cold start, but cold starts is when it runs fine, i also forgot to mention in the original post, but the fuel guage started acting all erratic right before this problem started getting bad, and i can also hear the fuel pump, like hearing it over the exaust when this problem starts acting up, like a loud hum you can hear very audibly, like i said you can distenguish the sound ever the engine and exaust

 

What DTC's were retrieved, and what order were they retrieved in?
Fuel pressure: Ignition in the RUN position, (don't start the engine) fuel pump running: Pressure must be 60psi to 66psi while the pump is running. Fuel pressure must remain above 55psi for at least 10 minutes after the pump shuts off. Post your results.

GM does not publish any "engine running" fuel pressure specs for this engine. There are far too many variables involved so running pressure is meaningless. All pressure readings are taken with the engine off.

 

could be possible mass air flow sensor. sometimes will not set a MIL. I was also thinking TP sensor. but that usually only happens for a short period of time and usually sets MIL

 

ok this is what i have come up with, i tested it today and the codes that came up are 3 o2 sensor codes , and a random misfire , but the o2 sensor is probably my fault, about a week ago when i had it tested, it said o2 codes, and i looked and evidently whoever put an exaust on it before i got it forgot to plug a sendor back in, so i cleared the computer and rehooked the o2 sensor, then the day after that is when it started really acting up, bogging down and almost dying when i hit the throttle, the check engine light came back on no doubt because of the misfiring, but i stopped and unplugged the o2 sensor that i found previously unhooked, i thought , well maybe it was unhooked for a reason, but it didnt matter if it was hooked up or not, it still acted the same, but like i said, the codes showing now were 3 o2 sensor codes, and a random misfire code, i changed the fuel fillter, the air filter, plugs and wires, and i replaces the catylitic converter, .... today after i changed the plugs and wires, it seemed to run alot better, but still after running for about 30 mins, you can start to hear the loud whine of the fuel pump, and it starts to lose power and bog down, and as far as the order of the codes, it was 3 o2 codes and the misfire code,, in that order, .. but back to where i was, fuel pressure,... cold start, 60 psi when turn key, stays close to 55 when pump stops, after i ran it a while today and after it stared acting up again, i tested it once again, these are the results, .. i had to turn the truck off to hook up the fuel pressure guage, which is in itself aggrevating, because when i cut the truck off and then back on, it stops bogging down until you run it again for a little while, and i wanted to test it when it was bogging down, but i couldnt get it to do that again after the restart, but you can still hear the whine of the fuel pump, its pretty loud, but turn key, 60 psi, pump shuts off, and immediatly it started losing pressure, it took only 13 secs to go from 55 to 40, then about another 30 secs it drops to 30, then about another min, its at 20, ...ect, it looses all pressure within 5 mins, so then i started the truck, it stays at 51 psi, when you rev it up, it jumps to about 60 really quick, then back to 50 or so, like i said i replaced the air filter, fuel filter, catilytic converter, plugs and wires, ... i dont think its the tps, because it idles fine and the throttle response is fine, it is just acting like its getting a line colapsed or something, but its just weird that it is intermitten and only happens after you have run it for a while, and whats even stranger is that when you stop the truck and restart it, the proble is still there but not as bad, and it gradually comes back, .. for example, the other day i barely made it home, it started with it bogging down around 3000 rpm, then it gets worse, 2500, 2000, 1500, 1000, and finally you can barely touch the throttle and it will stall, it has no power to even climb a small hill , just loses speed, but once it stalls or i shut it down, it will run good for about 2-3 mins, then it starts all over again, and like i mentioned the fuel guage jumps all over the place, but sometimes it works right, the fuel guage working or not working does not coincide with the truck acting up, i appriciate all the help from everyone, i hope we can come up with a solution for the problem

also every few days, i can stop at the store and it wont start back up, after i mess with it for 10 15 mins, it will finally fire up, its weird, im wondering if that has to do with the fuel problem or if its a security thing, because the security light will stay on sometimes, and flashes sometimes, it may have to do with the aftermarket stereo, the codes that come up the first time i tested it were like 13 codes , most of them were abs related, abs control modual, and right front wheel speed sensor, then o2 sensor codes , thats when i realized that the right front o2 sensor was unplugged, but then the last code was p1631 theft deterrent system, incorrect password, i dont know it that has to do with the other or not, just something else wrong

 

Still need to know what the DTC's are. What are the numbers? Plug the O2 sensor back in and leave it connected. Save your time and energy with engine running fuel pressure, it means absolutely nothing.

The problem is borderline low fuel pressure and excessive leakdown. Your next step is to check maximum fuel pump output pressure and leakdown. You will need to modify your fuel pressure tester so that it connects directly to the fuel filter outlet. All fuel pressure and flow must end at the pressure tester. This is commonly referred to as "dead head" pressure. We need to know what the pressure is when the pump is running, and we need to know what the pressure is 10 minutes after the pump shuts off, that's all. Post the results.

If you are not comfortable with this procedure, take it to a professional.

 

i dont have the code numbers, but the o2 codes that came up, they said bank 2 sensor 1, no activity, and i am guessing this is because it was not hooked up, the other code was p0300, random cylinder misfire, and the last one was p1631 theft deterrent, incorrect password, the abs codes that i mentioned earlier, were actually first on the list, but they were codes that started with C then 4 numbers, and i dont know how to look them up, but they were for abs control modual, and the front right speed sensor, i have no problem hooking the guage up to the output on the filter, i am a pretty good mechanic in my own right, bu this problem im having is so random and erratic i am having a really hard time diagnosing it, i thought to just replace the fuel pump, but i feel like there are other issues too, but just dont know what they are, but i will post my results when i get the dead head pressure tested

 

dead head fuel pressure test results : 70 psi, after 10 mins 46 psi, which is alot different from the previous test, at the fule test port, when i got 60, and within 5 mins it was 0 psi .... hope this helps me and hope this is what you needed captain hook