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Hi, I’m really hoping someone here can help me figure this out. My 2005 Land Rover LR3 with 126,000 miles started acting up a couple weeks ago. It began with just a poor idle. I’d describe it as an occasional rhythmic “BLURP”…??? Kind of like a mini backfire that you can’t hear but you can feel. That progressed after a couple of days to a full blown rough idle with loss of power and rough acceleration. Thats when I started getting the DTC’s. Cylinder 8 at first. Changed the coil from 8 to 6 and drove it a bit. That’s when I got codes for 3, 4, and “RANDOM MISFIRE” followed shortly there after by the dreaded “REDUCED ENGINE PERFORMANCE” message on my dash. BTW, cylinder 8 never threw a code again. So I changed the MAF, reset the driver adaptaion log and reflashed the TCM. That seemed to fix the issue until I let it sit for a few hours. When I started her up… Same thing. Rough idle, random misfire and REDUCED ENGINE PERFORMANCE. I let it be for a bit because I’m trying to avoid throwing parts a the car in the hopes of fixing it. So over the past week I noticed that if I drive the car long enough the symptoms go away completly and it runs perfect. So I started collecting live data via the torque app and I came to find that when the engine approaches 170 degrees the engine starts to smooth out. by full operating temp of 190 or so it runs and performs perfectly. this is leading me to suspect a sensor that gauges temperature. I’d really appreciate it if anyone has any input on the subject because from what I’ve read anything gauging temp usually results in bad performance when hot rather than cold.
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I’m going to apologize in advance for all the pictures. I couldn’t figure out how to export the report. Here are the freeze frames for the codes I got on my home this morning after clearing the previous codes. I think this one is for cylinder 4
Also when I got home I swapped # 3 and 4 coils with # 5 and 6 so now they’re on a different bank. I drove around a bit but I didn’t get a code yet. My hands were freezing so I didn’t pull the plugs. Tomorrow should be a bit warmer so I’m going to give the plugs another try tomorrow.
The Lt/St fuel trims max out negative on both banks. No other error codes besides P0304?
The fuel trims you posted before on page 2 looked normal but page 4 are maxed out.
Page 2 data and page 4 data on different scan tools?
Can you read when engine goes into closed loop on either scan tool?
Wonder if fuel system status 2 means closed loop?Can you select just fuel trims/ engine load/RPM/ECT/MAF/MAP/O2 sensor voltage to monitor?
If so compare them at idle and at 2500 RPM.
Would like to know why high negative fuel trims on both banks.
Fuel rail pressure reads .06483 psi. Maybe means 64.83 is this normal pressure?I noticed that as well on original set of data when you stated it was warm it demonstrated normal fuel trims and then on the data with the DTC’s it showed maxed out – Fuel trim indicating a rich condition. Can you show O2 voltages for up stream and down stream on both banks as well. Do you even notice that is smells rich when driving on start up.
The second set of data was what I collected from JLR SDD which is Land Rovers diagnostic program. It’s run on Windows XP with a DrewTech Mongoose cable interface. The previous data was collected using a Bluetooth OBD2 and the Torque App. I’ve only used the JLR for reflashing. I know it has more capabilities to collect data. But since it’s so complicated Land Rover Tech’s have take a class on it. And there really is no information on how to operate it. It’s geared for a professional garage so there has to be something. Anyway, that should have been a closed loop. I let the car idle for about 5 minutes prior to pulling away. Then I didn’t make it a block before I got the trouble code. Once again, thank you for taking the time to help!
jjohnson1, it does smell very rich when I start up. Being winter I’ve had the windows rolled up so I didn’t notice until just now when I went out to check
Okay, I did some research and found where I can monitor live information. It’s hidden very deep in a section of the program nefariously named “DATA LOGGING”. I’ll post results tomorrow. Too cold to sit in the car and screw with the laptop. I just thought I’d share the irony
I never was able to get my Land Rover program to load the PID’s onto the graph. But I ended up changing out cylinder 6 with a new coil. Still got a misfire for 6 and 7. So knowing 6 is 99.99999% good I swapped 7 with 3. Cleared all the codes and reset my PCM. Drove a bit and got got the same 306, 307 and 300. At least this time the problem didn’t change to the bank I put 7 on. I’m at my wit’s end so if anyone can offer some guidance I’d appreciate it
The torque app data you posted on page one looks normal at idle and 2500.
If still the same maybe revisit the gasket leak test.
If gasket sealing as engine warms up then the engine running water test may not be applicable.
A shop engine cold / smoke test is probably the best in this case.You could tighten the intake bolts a bit that are located nearest the misfiring cylinders runners on the off chance it is an air leak.
If you can verify running fuel pressure and monitor it when engine shut off. This is to test possible injector leak that could cause misfire on cold start.
Doesn’t misfire on warm start correct?Sorry for no reply. Have been on vacation with son before he leaves for Navy. Have you found out anymore details on your misfire.
Well she’s finally fixed! Took a long test drive today and it was smooth as silk. I originally gave in and replaced two coils #6 & #7 to no avail. Still had the hard misfire on 7 with pending codes for 6 and random misfire. So I replaced all the coils on bank 2 along with new plugs. The plugs on bank 2 were a little worn being 6 years old with about 50,000 miles on them. They were ashy white (lean I think). Still no luck… 300, 306, 307… Then I checked every cylinder for spark (guess that should have been step one) and used my newly acquired stethoscope to listen to the injectors. Everything seemed fine thus far. I had fuel, fuel pressure and spark. Double checked for manifold leak and nothing. So I decided before I do a leak down and compression test I’d pull the injectors and run them through my homemade pressure cleaner. Some injectors were a little grimy and the lower O rings that insert into the engine were a bit dry and malformed but other than that the spray pattern was good and volume seemed okay. So I replaced the o rings. Before buttoning everything up and admitting defeat I hit up some Land Rover forums. A few guys reported that changing only the coils that threw a misfire code didn’t resolve the issue. They said they ended up having to replace all eight. So that’s what I did and it worked. I’d like to thank everyone for their time to help and for everyone’s concern. jjohnson1, good luck to your son and his Navy career!
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