Ls running rough p0171,p0175

[maxlsv8]

I have 2001 ls v8, 118k miles; It started running rough after an extended period of idle (30 min). Originally I had code for cyl.7 missfire, I replaced the coil and that did nothing (I'm assuming that cyl. 7 was result from engine running rough). So I cleared the faults then P0171(bank 1 too lean), P0175(bank 2 too rich) came back. So I tried a few things: I replaced all the plugs with new NGKs, I cleaned maf sensor, through the years I replaced 6 coils and it still has 2 originals left they are fine. I did fuel pressure test: I bypassed the fuel filter and installed the gauge inline with the result 32-34psi with the gauge fluttering as the car is trying to idle. When I had the cyl. 7 missfire code I swapped the fuel injectors 6 and 7 around to see if the code would return and it has not returned yet, but the car is still running rough.
I'm pretty much stuck with what I can do on the car or test on the car, Is
32 psi normal at idle or should it be higher? The codes are not making sense to me either: bank 1 too lean bank 2 too rich.

 

[SlickLS]

I would go check your connection on your fuel injectors. My car did the same thing to me and it ended up being a loose connection. Start your car and then take a flathead screwdriver and press on the connection.

 

[DENNISJR60]

I have 2001 ls v8, 118k miles; It started running rough after an extended period of idle (30 min). Originally I had code for cyl.7 missfire, I replaced the coil and that did nothing (I'm assuming that cyl. 7 was result from engine running rough). So I cleared the faults then P0171(bank 1 too lean), P0175(bank 2 too rich) came back. So I tried a few things: I replaced all the plugs with new NGKs, I cleaned maf sensor, through the years I replaced 6 coils and it still has 2 originals left they are fine. I did fuel pressure test: I bypassed the fuel filter and installed the gauge inline with the result 32-34psi with the gauge fluttering as the car is trying to idle. When I had the cyl. 7 missfire code I swapped the fuel injectors 6 and 7 around to see if the code would return and it has not returned yet, but the car is still running rough.
I'm pretty much stuck with what I can do on the car or test on the car, Is
32 psi normal at idle or should it be higher? The codes are not making sense to me either: bank 1 too lean bank 2 too rich.

How do you check codes on your car? Do you take it somewhere or can you do this yourself?

 

[SoonerLS]

How do you check codes on your car? Do you take it somewhere or can you do this yourself?

For his LS, all he needs is an OBDII reader, which you can get for under well under $100, or you can take it to AutoZone, O'Reilley's, etc, and they'll pull the codes for free. For 2nd Gen LSes ('03-'06), you need a CAN-compatible scanner, like AutoEnginuity's ScanTool.

According to AllData, 32psi is a little bit on the low side (it shows 35-70psi as the range), but I don't know what the LS usually runs. I know my Explorer (which also uses a returnless system) is supposed to run around 65-70psi.

 

[joegr]

...
According to AllData, 32psi is a little bit on the low side (it shows 35-70psi as the range), but I don't know what the LS usually runs. I know my Explorer (which also uses a returnless system) is supposed to run around 65-70psi.

The gen II service manual says that 30 to 55 PSI is normal, so 32 would be okay, unless the pressures are different for gen I.

 

[joegr]

How do you check codes on your car? Do you take it somewhere or can you do this yourself?

Auto Enginuity makes a scan tool that lets you get to a lot of the LS specific stuff, as well as the generic codes. It's somewhere in the $400 range. You can get a generic (make sure it supports CAN) tool for less then $50.

 

[tireman]

manual says

check air intake system for leaks
check air cleaner
verify fuel level
check pcv system v6, the v8 has another setup
check for disconnected spark plug wires
check for vacuum leaks
did the customer run out of fuel?

I would say look for vacuum leaks, or the IAC valve is carboned up or failing. Your old machine, like mine, is probably in need of some new rubber hoses. I replaced all my vacuum line hoses.

 

[maxlsv8]

Figured it out; the drivers side chain tensioner failed, the plastic piece broke off went in between the gear and the chain and the chain jumped and skipped time. But when the engine ran there was no abnormal noises coming from the front of the engine.
I just put it all back together and it runs great!

 

[wallyj]

Figured it out; the drivers side chain tensioner failed, the plastic piece broke off went in between the gear and the chain and the chain jumped and skipped time. But when the engine ran there was no abnormal noises coming from the front of the engine.
I just put it all back together and it runs great!

How big of a job was this? Can you please supply more details if possible.

Thanks