Isolated P0171

hey all,
New to the forum and having a little trouble with my 4.0 2001 explorer. K&N filter.

Have had this ode for a while and it is driving me nuts. Here is the run down:
Changed fuel filter
Cleaned MAF and IAC, and intake.
IAC new 1 year ago.
Fuel Pump replaced 2 years ago.
New upstream O2 sensor, I know!
Did the intake leak test, none.
CHecked the PCV valve
changed the plugs, wires


so here is the problem: The car is hard starting, runs fine. When I leave it for any length of time it starts hard. It did starting thing about 2 weeks before the fuel pump went out.

My question is would a fuel pump cause this isolated code, or could it be a faulty EGR? The fact that I am not getting the P0174 is a little perplexing.

ANy other thoughts would be great. By the way I am in phoenix where it is 115-120 could this cause any of these problems?

I don't recall if both banks have a fuel pressure regulator on the fuel rail, or just one regulator for both banks. I'd suggest you start by adding a bottle of fuel injector cleaner to the fuel tank and maybe replacing the fuel filter, general tune-up stuff (which you've already done most of).

As I first started reading your description, I too thought EGR until you mentioned you don't get the P0174. Seems like, in addition to checking the intake for leaks, you should check for any other vacuum leaks.

Do you happen to have access to a scan tool with the component parameters capability to check for failures that may not cause a check engine light?


-Rod

Unfortunately I do not have access to a scanner. I want to know the fuel trim settings, but not possible at the moment. THe fuel filter is less than a month old, that was the last thing I did. I am going to check my fuel pressure this weekend and see if my fuel pump is taking a dive again. THen I am going to clean the egr and passages and replace the intake gaskets, and vacuum lines. Also going to look at the EGR vacuum reg.

I have gone over all of the vacuum lines, but couldn't find a leak.

Thanks