I have a 2001 Chevy Impala with a 3.4 l. Last week I replaced the idle air control valve which was a problem for a while because I had the car stop at an idle and shut off. I plugged in my Alltel hand tool this last week and found out that the EGR valve how old was coming up. I replace the EGR oh, the car ran fine for 3 days and now the car stahl'* and will not start back up when it has been running for a while. That seems to be a brand specific problem, I am an ASE Master Certified Technician, however my specialty is in Audi and Volkswagen. I plugged in the Alltel and it gave me a lean code on bank 1 which would indicate either a bad fuel pressure sensor or the fuel pump has failed in a way that when it runs too long he gets too hot and therefore the pressure it produces drops as time goes on. I know fuel pumps fail in many different ways. I am not sure if it is a fuel pump or a fuel pressure sensor and I have not put on a gauge yet, however I was thinking if I hooked up my scan tool and watch the fuel pressure in the live data as the car ran over time it should drop gradually which would indicate a bad fuel pump. I also got word that a bad mass air flow sensor would cause this kind of symptom as well. Either it is dirty or it is bad. Overall the car starts up and runs just fine after it has been sitting and gotten cold. When it runs over time it just doesn't start back up. Anybody have any clue of what'* going on here?

[QUOTE=HetzC22;1643540]I have a 2001 Chevy Impala with a 3.4 l. Last week I replaced the idle air control valve which was a problem for a while because I had the car stop at an idle and shut off. I plugged in my Alltel hand tool this last week and found out that the EGR valve how old was coming up. I replace the EGR oh, the car ran fine for 3 days and now the car stahl'* and will not start back up when it has been running for a while. That seems to be a brand specific problem, I am an ASE Master Certified Technician, however my specialty is in Audi and Volkswagen. I plugged in the Alltel and it gave me a lean code on bank 1 which would indicate either a bad fuel pressure sensor or the fuel pump has failed in a way that when it runs too long he gets too hot and therefore the pressure it produces drops as time goes on. I know fuel pumps fail in many different ways. I am not sure if it is a fuel pump or a fuel pressure sensor and I have not put on a gauge yet, however I was thinking if I hooked up my scan tool and watch the fuel pressure in the live data as the car ran over time it should drop gradually which would indicate a bad fuel pump. I also got word that a bad mass air flow sensor would cause this kind of symptom as well. Either it is dirty or it is bad. Overall the car starts up and runs just fine after it has been sitting and gotten cold. When it runs over time it just doesn't start back up. Anybody have any clue of what'* going on here? It doesn't seem that a fuel pressure sensor would go bad under heat, however I'm not a GM Tech and I'm not sure. I have seen fuel pumps go out in different ways, and in this way it seems like the windings and the pump have weakend, and therefore when it runs longer and longer the heat causes resistance which therefore restricts electrical flow. I may be wrong.

As a CMAT why would you condemn the fuel pump for a bank specific code?
When it will not start do you have tach signal?
Whether it'* an Audi or a Honda the engine management system work the same way. They call things by different names but the result is the same.

so like I said, fuel pumps fail in three or four different ways. This fuel pump on this car is not completely gone, however when it gets hot the pressure from cold 55 PSI proximally goes down to about 28 to 29. The car runs, however after running the car for a while the fuel pump gets hot and does not supply the proper fuel pressure. When you step on the gas it is sluggish, and generally if you get it on the interstate it takes quite a while to get it up to 65. If it were a coil pack issue, it would sputter on an off like most GM coil packs I have experienced and replaced. This vehicle does not do that it runs perfectly normal at idle and as long as I don't shut it off, it runs. But as soon as I shut it off, it has to cool off before it will run again. I got a lean code on bank 1 which could also mean a fuel pressure sensor as well. Any more thoughts on this? I replace the idle air control valve and the EGR valve which were both bad three days ago oh, and the car ran peppy again. I knew the idle air control valve needed to be replaced because I kept cleaning it twice and they only last so long. The RAC was not bringing up any code because it was just carbon buildup in the step motor itself. But when I hooked up the Autel when the check engine light came on the e g r valve was stuck open halfway. After that everything ran good for 3 days and then now the car runs sluggish when you give it load.

You know you have a bad fuel pump.

Have you checked fuel pressure with the vacuum line to the fuel pressure regulator disconnected?

How do you know that the fuel pump is getting hot?

How full is the fuel tank?

Is the fuel pressure that you are reading from a gauge connected to the fuel rail?

How many miles on this car?

How many miles on the current spark plugs?

He said it drops to 28 while driving. Nothing left to do here until he fixes that.

Engines will always run like **** and throw lean codes when the fuel pressure isn't at the minimum Sure, it will start and idle at 28psi, but when the injectors demand more fuel at higher loads, the pump isn't providing it.

Like Carfixer already indicated, correct the fuel pressure issue and move on.

I an ASE Master Certified Tech, however that doesn't make me an expert at GM. I specialize in Audi Volkswagen which I went to school for. I know the principles are the same in general, however when I have had experiences in the past with GM, with this particular engine having a coil pack, when that goes, usually when you step on the gas it is a very rough in and out misfire until you reach speed. The misfire only occurs when you're trying to apply load to the engine. This particular incident oh, the car is sluggish going up hills, and there is no rough misfire. It runs fine at idle. I hooked up the Autel, and it gave me the codes for the idle air control valve which I knew was a problem for a long time because I took it out and cleaned it twice and the car would stall if it got gummed up. The new code I got was for an EGR valve. EGR valve was stuck halfway open. After replacing both of those, the car was Snappy and ran up hills and I could get it up to speed no problem on the interstate. After three days doing those repairs the car was sluggish. Now I think I have a separate issue, which I believe the fuel pump or the fuel pressure sensor is no bueno! Now the car will run, however it is sluggish up hills and will not go over 50 miles an hour on the interstate. If you shut the car off after it has been running for a little bit, it will not restart. It kind of leads me to believe that something is getting hot like the fuel pump which may not be totally gone, however the pump maybe getting hot, and if you know electrical principles, the coils in the pump may be shorting out or partially shorting out. Therefore it takes time for it maybe it'* a cool off. What'* really doesn't make any sense if the pump is sitting in gasoline which is cool anyway. I am thinking more towards the fuel pressure sensor because it sits in the engine compartment and gets hot. I did get a lean hold on bank one when I had it hooked up to it after I did the original repair. However now my Autels subscription has run out and I can no longer access live data or any function of that scan tool. If you have any ideas why the car would be shutting off after running for a bit and then restarting , but still sluggish going up hills, and when a load is applied it has no power. I guess I have to either re-subscribe or find another scan tool! If anybody has any ideas let me know!

[QUOTE=HetzC22;1643570]I an ASE Master Certified Tech, however that doesn't make me an expert at GM. I specialize in Audi Volkswagen which I went to school for. I know the principles are the same in general, however when I have had experiences in the past with GM, with this particular engine having a coil pack, when that goes, usually when you step on the gas it is a very rough in and out misfire until you reach speed. The misfire only occurs when you're trying to apply load to the engine. This particular incident oh, the car is sluggish going up hills, and there is no rough misfire. It runs fine at idle. I hooked up the Autel, and it gave me the codes for the idle air control valve which I knew was a problem for a long time because I took it out and cleaned it twice and the car would stall if it got gummed up. The new code I got was for an EGR valve. EGR valve was stuck halfway open. After replacing both of those, the car was Snappy and ran up hills and I could get it up to speed no problem on the interstate. After three days doing those repairs the car was sluggish. Now I think I have a separate issue, which I believe the fuel pump or the fuel pressure sensor is no bueno! Now the car will run, however it is sluggish up hills and will not go over 50 miles an hour on the interstate. If you shut the car off after it has been running for a little bit, it will not restart. It kind of leads me to believe that something is getting hot like the fuel pump which may not be totally gone, however the pump maybe getting hot, and if you know electrical principles, the coils in the pump may be shorting out or partially shorting out. Therefore it takes time for it maybe it'* a cool off. What'* really doesn't make any sense if the pump is sitting in gasoline which is cool anyway. I am thinking more towards the fuel pressure sensor because it sits in the engine compartment and gets hot. I did get a lean hold on bank one when I had it hooked up to it after I did the original repair. However now my Autels subscription has run out and I can no longer access live data or any function of that scan tool. If you have any ideas why the car would be shutting off after running for a bit and then restarting , but still sluggish going up hills, and when a load is applied it has no power. I guess I have to either re-subscribe or find another scan tool! If anybody has any ideas let me know! I need spark plugs, wires, and I do not know about the coil pack were replaced about 2 years ago. Far as I know if that'* something that should look at let me know! Thank you!