Lean on me

[Greg Sali]

Ok a little knowledge can be a dangerous thing, and I have as little as anyone. Here is my (ok, one of my problems), 02 Trac with 41,000 miles. I've been getting CEL with P0171 and P0174 for about a month. I got on the site and checked all the relevant posts. It is not the elbow. I took the whole thing off and checked hoses on both ends and vacuum checked the hole unit, it is good. Had no drivability problems at first, now I'm getting a stumble and it died twice at idle. I have a scanner so I just reset the light every time it comes on. Yesterday while pulling a trailer, I got a flashing CEL for about 15 seconds, then it went out.



Help Mr. Wizard, I don't want a lean Trac anymore.

 

[Todd Z]

if your 100% sure it is not the elbow, it could be a dirty MAF sensor, Try cleaning that, Clean the IAC for G.P. and then start checking for a vacuum leak, either with carb cleaner or the propane test..



There are issues where the intake gasket goes bad, MAF, Temp sensor, or a hose is bad.

Todd Z

 

[shawn stonbraker 2]

Try cleaning your IAC valve for the stumbling and rough idle. As for the code, most of the time it's been the elbow. Maybe someone here can point you in the right direction. Probably some type of vacuum leak.

 

[shawn stonbraker 2]

There you go. Todd is a faster typer then my one finger typing.:lol:

 

[Greg Sali]

I already cleaned the MAF with the approved MAF cleaner from NAPA 3 times. Cleaned and lubed the IAC. Checked for a real vacuum leak with the old "point an unlit propane torch at the likely spot and listen for a change in RPM" trick, didn't find anything.



The CEL seems like it is a timer. It comes on 3 minutes after I start the Trac almost every time I drive it now. I just started leaving the scanner in the Trac and resetting the CEL right after it comes on. It usually does not come back on again until I shut down and restart.



How about that flashing CEL? Never heard of that before.

 

[Ron N]

You might change the fuel filter as well that can cause a lean engine, also check for leaks or restrictions on pcv system._Ron

 

[Greg Sali]

fuel filter was the first thing I did. I'm not sure what a restriction in the pcv system would look like.



Could the DPFE cause this?

 

[Kevin Palmer]

You may want to get your fuel pressure checked as well. If it is low you will get the same lean reading as the injectors don't really know anything more than how long to be opened or closed, they pretty much go for the ride and do what the ECM tells them to do based on input from various sensors.

 

[Greg Sali]

Is checking the fuel pressure something I can do? What should the pressure be at the injector rail?

 

[Greg Sali]

more information, this morning it pitched a P0401 code, after reset, the CEL has not come on after 2 trips. Is this a PDFE sensor problem?

 

[Tom Schindler]

P0401 Exhaust Gas Recirculation Flow Insufficient Detected



I would say replace the DPFE sensor.





Tom