A couple of weeks ago LR3 started running rough at idle and had no power. Took it in to have codes read. Got P0305, P0300, P0171.
Took it in and they ran diagonistics to check for air leaks, misfires, and fuel. Told no air leaks, and fuel supply is good to the engine. Said I should have cylinders 4, 5, & 6 coils, and #5 spark plug changed. Still no change. Had bank 1 back O2 sensor changed, thinking it was bad and telling ECU that truck was running lean and over- correcting by dumping too much fuel into the engine causing the misfires. Not the problem either. I have spent so much time and $$$ and am not any farther along with the problem(s). Anyone have any ideas?? Sensors? EGR Valve? Throttle Body Sensor? Other O2 Sensors? Dealership seems to be perfectly content with taking money and not fixing the problem. I'm thinking maybe a match and some gasoline will fix the whole thing.

 

swap the injectors around. That might be your issue.

if the injector is bad then its probably giving you a low dose of fuel causing the lean code.

if it was me, I would have swapped coil number five with seven and spark plug number five with number three.

 

Thank you for responding! I swapped fuel injectors and reset. Drove around for about 30 mins or so. Running better, but still running rough. Check engine light did come on. Ran it by auto part store and had the codes read. Got a P0171 code and no other codes. Gotta be front O2 sensor on left, right?

 

no, five bucks says you have an issue with clogged injectors.

I recommend a bg fuel injection service. it works, trust me fixed quite a few of those vehicles with it.

 

Found this thread and I need some help as well. I just got my truck intake smoke tested to test for any vacuum leaks, changed the coolant, changed the thermostat, and changed the MAF. I have the lean codes P0171 and P0174. I was wondering if I needed the injector cleaning service to maybe clear this issue up. Other than the codes the truck does not drive different other than when the truck is first started in the morning the idle drives up and falls almost to a stall then recovers. Help?

 

Also, my mechanic told me that my fuel pressure was about 70 psi instead of the 50 to 60 psi as required by the spec. Maybe fuel injector cleaning??

 

Well you can try it, but high fuel pressure causes rich codes , not lean codes.

 

Rovin4life I think you are correct. The only other thing I can think of is a vacuum leak on the inside part of the intake manifold. Never seen a smoke test pick that up on an engine. My mechanic did the smoke test and said that I should take my LR by the dealer and let them do a scan on it to find out what could be the issue. But unlike my mechanic, the dealer will hit me for the big bucks! But, if I want the truck to last I may have to bite the bullet!

Any thoughts to what else I can check?

 

yeah, hook up a oil filter inside the air tube and tighten it down. that way when the vehicle starts the engine will only start if it has an air leak.

 

you can locate the air leak and from there replace the part.