Keep causing a skip or lugging code P0171

I need help with this code I know its a lean issue on bank 1 but what r the steps to eliminate things I already tried replacing the intake( plentum) gasket what else can I do? I dont have much money to keep replacing all these parts. The engine blew going 75 in cruize control so I replaced it with same thing. Now it is doing same thing. Iam going out to the garage to clean the maf sensor and check the crankcase vent tube, where is that on this engine? If some 1 can help me solve this problem I will donate whatever u want well almost anything u know what I mean. There is also a long metal tube the diameter of a nickel behind engine going down to the ground well I ft from ground that is not connected to anything and it is not the transmissin dipstick tube but runs along real close to it

I had to use a pry bar on the egr valve to get it to lalign to the two mounting holes for the bolts to go on and crushed the top of egr valve would that affect its operationand if im right the egr valve is the tube from side of carb so to speak to the exhaust manifold on bank 2 side correct?

How di check for vacume leaks and ca u answer some of the other questions in the paragraph plz ty so much I will try the opts u gave first then i'll ask for more help and plz look 4 me on here to keep me in check and in your mind thx

Ok now how bout egr thing I asked if it is dented in a bit will that cause it to not operate properly? What does the egr do? Can that be the problem? Also I did just replace the pcv in valve cover and now it sounds like I have a engine knock really loud. I did nt replace with oem or adequit part just saw one that looked like it and used that. Is that normal?

I replaced my old engine with a 2000 mercury grand marquis engine. I had to change the intake(plentum) and the injectors and use my 2 coil packs instead of the coil paks on the spark plug itself. Cuz of the intake wouldn't match up to the air intakei had for my truck. Is that ok also. What a head ache I have so sick of this. The other engine was doin the same thing then the engine blew 2 cylinders, bent and destroyed 2 spark plugs ruined a coil pak and bent and ruined the lifters well the lash adjusters. I need help so bad. I will try all the things u sugested tomorrow morn and will be looking forward to your answers to my next questions tomorrow morning or mid day sometime.
Thx again u r a savior to me if this all works without replacing all the sensors and other related parts until im broke

Ok well egr is dented at the top of it where the smallest circle part of it and the pcv valve is knocking when installed stops knocking when I take it out of valve cover and engine bogs maybei should just replace the egr as a precaution and who knows maybe it will be the problem

Ok I cleaned the maf sensor, I replaced the egr and the pcv valve and replaced all the vacume lines that I saw what else shouldi do? I am going to return the egr vlve as it did not change the way it ran a bit and I could use that on something else that I need. Do u think I should replace the bank 1 o2 sensor? Or what should I do bext plzzzzzzzzzzzzzzzzzzzzzzzzz help

Ok- My truck kicked the infamous p0171 codes and gave missfire codes on cyl 1 and suffered a major power loss though it has 35" tires with 4.10 gears. I replaced every plug/wire, new coilpack (though it was just a year old) replaced 02 sensors, new MAF sensor, new IAC sensor, new pcv valve, checked hoses for vacuum leaks, new fuel filter, ran seafoam through vacuum line from brake booster to smoke out the system. Still no improvement. I took it to the dealer who diagnosed that everything looked acceptable except cyl 1 failed the leakdown test. Suggested a new motor since the rings were probably shot. I had a new Jasper put in- idled better but still no power on hills/hard acceleration. I decided to go with catalytic converters. Temp tested between the 2 banks and bank 1 (pass side) was extremely hotter. Replaced both sides (all 4 converters) to be safe. Still no power improvement though I had no check engine light. One day later my CEL came on. Hooked it up and it's the same p0171 code saying Sytem Lean on Bank 1. I'm bank at the beginning though my bank account is almost $6,000 lighter. I guess Fuel delivery is my next route.

I went and replaced the pcv valve with the oem and the knocking is fixed but the hesitation, lack of power and rough idle are still there. And I stated b4 in the last reply I replaced the egr and the truck still runs like crap. So im gonna return the egr and put the original one back on and save the 50.00 for the real part. Oh and I cleaned the maf sensor and the air filter.

Also I thought I would mention that when I unplugged the maf sensor the engine did die therefore it is working properly

Well the dealer didn't replace the motor. They only noted that cylinder 1 was showing much lower compression, like 60 lbs I believe. They also said that it was leaking down which was probably a sign that the rings were shot (Im assuming compression) and they suggested a new long block. This was after I had replaced all of the sensors and what not, so I figured this could possibly be where the misfire was coming from. If it had no compression to respond to the combustion, then the computer would read it as a misfire, this causing the lean condition on that bank. We decided cyl 1 was so shot that a new motor was needed anyways, and could be a cause for the power loss. So I took it elsewhere for the Jasper swap. Myself and a couple of family mechanics checked for vacuum leaks prior to the dealer visit. I had already changed the pcv valve and inspected the hoses/elbows coming from the pcv to the throttle body and around the EGR. Wouldn't the DPFE kick a lean code for both banks? Should I buy an injector and try it on cyl 1 since that is where all of my problems have shown? What about vacuum leaks on the brake booster? Wouldn't that cause both banks to read lean though?

I also need the next step after the #41 u gave me.

Thanks so much for the quick replies. I probably should have looked more into the possibility of it being a valve. Esp since the catalytic converters on bank one clogged. However, I didn't have the time to put into pulling the head since I just moved and don't have a garage here and needed my truck back asap for work. I know that cylinder 1 was firing electronically, but I'm almost convinced there was an absence of fuel there causing the lean reading. I'm going to buy one injector tomorrow, disconnect the battery to reset the computer, pull the fuel rail and replace the injector on cylinder one. Hopefully that is going to be the root cause of everything. **Injector clogs/leaks, causes misfire, caused catalytic converters to clog after driving for way too many miles running lean while trying to troubleshoot, then the exhaust backed up, burnt the valve and caused the cylinder compression failure.** This is my theory anyways and I may be completely off. But I have way too many custom hours/money into the truck to turn back now. Yea I could have bought another truck for what I have into it, but atleast I will know what has been done to this truck! Any ideas if the new injector doesn't fix the problem?