Hi. I have a question about why my 2.5 v6 still has issues. I installed new fuel pump, had 22 psi now has 49PSI. Installed plugs, wires, dist, egr valve, map sensor, upstream o2, like almost everything you can do when you get code p0171. It has this baby backfire in really close intervals coming out of the tailpipe while it idles. Or while I drive it. It sounds like popping or poofing. Like poopf, poopf, poopf every4 or 5 or 6 secs or so. It never stops and car has to warm up for a minute before it starts this inevitable boping over and over out of the tailpipe. Its like a backfires little brother and it never stops like a backfire does. A backfire goes POW but doesnt do it again for a few. These just keep doing it over and over forever until you cut the car off. It idles aqt a perfect 750rpm's. Its the weirdest thing Ive ever seen. Runs better when going faster like in 2nd or drive. Not so good at 0-20 mph or at idle. If I rev it up pretty hard it smooths out good and sounds fine. I dont get it. Anything y'all can advise me is highly appreciated, a lot. Thanks!

 

Might want to check this page:

OBD-II DTC: P0171 System Too Lean (Bank 1)

The code means that the engine is running lean on the #1 (rear) bank of cylinders. It's either too much air or too little fuel for some reason. Your challenge is to figure out the reason.

 

I've had the same code pop up on me once or twice with my 2000 JXI. (2.5L, of course.) Dump a can of Seafoam into the gas tank and the code will go away once you're through about half a tank. It just needs the injectors cleaned out a bit, it happens with the 2.5L quite often, especially if you frequent old, cheap gas stations. Lots of muck can get into the system.

 

Note: This is a reply for the P0171 code itself, assuming the car runs okay otherwise. It sounds like you've got further issues than that, and I've never heard of this miniature backfire 'poofing' you're getting.

 

Yea, it just sits there backfiring over and over like the timing is off. Idles great at 750, fires right up, just coming out of the tail pipe is this "cough" I guess, every 2 secs, just over and over. I'm getting distributor tomorrow. Thats the only thing I can think it is at this point. Although the seafoam is def a good idea. And I will be doing that as well. But man, its like everything happened at once. Fuel pump, cel light came on, this poofing junk out of the tail pipe every second its running or driving. I'll post back if dist fixes it.

 

Consider replacing the crank position sensor. It's not nearly as expensive as the distributor, your original equip is nearly antique, and replacement isn't difficult (remove front tire to access). I had similar symptoms & it seems to have corrected the problem and when this thing goes you'll get random error codes.