Hi my rover has had a rough lumpy idle when warm. When I start the engine in the morning when cold the engine runs fast 2000rpms the it goes down to about 750 rpms after about 10 seconds, it has never done this before. I thought I might have a fouled sparkplug so I pulled them all out today and they all look dry and slightly white. I am getting 4 new codes P1171,P1174,P0171,P0174 the code reader says Bank 1 and 2 are Lean. My factory Land rover manual says they are Rich? Do you guys have any idea what is wrong?


Thank you,
Willie

2000 Discovery 4.0
225,000 Miles

 

This happend to my 2001 Land Rover, rough ideal, it would drop real low and almost stall.The check engine lite came one once just before it died, whn I turned it on the engine lite didnt turn back on.After some advice from my family mechanic, he said it was the ideal air valve,I replaced it and it runs like new, my advice to you is to clean it out with carb cleaner, and go from there.if it ends up being the O2 sensor do not drive it as it could ruen your o2 sensors.

 

Thanks for your reply ajmille. I took it out for a ride today. I did a few full throttle runs to see if any new codes come out and I did get two more. P0102 MAF signal minimum threshold, and a P0505 blocked Idle Air Control Valve. I will clean it out with carb cleaner like you said and see what happens. I hope the MAF is not bad. I will post the results for future referance.

Thank you ,
Willie

 

Next time, double check any information your mechanic gives you, he cost you a idle solenoid you didn't need. All that was necessary was to clean it and the t/body, $3 worth of carb cleaner, and you would have been fine.

 

just to let u know Disco Mike , I did clean the ideal air,which my Mechanic sugested and it still didnt work, which is the reason I replaced it.The little electric motor was seized in place.So cleaning wouldnt of fix it.With the new one the problem went away.Just to see what was inside of it I opened it and found the motor burnt up.

 

I cleaned the idle valve with carb cleaner. The engine still idles rough. Maybe I have a burnt out motor too. I also spayed carb cleaner at the intake gaskets while the engine was running and it did pick up RPMs when I did this so it looks like I have a gasket leak. I will change the gaskets and see if that helps.

Willie

 

You did the right thing. Normally the solenoid just needs to be cleaned, rarely does it freeze up.

 

Also clean your t/body. How many miles on your engine, do you have any codes, when was it last tuned along with 8 mm wires.
Don't jump into a new solenoid until everything else is changed and that vacuum leak is fixed cause there are many causes for a rough idle including a head gasket.

 

The Rover has 225,000 miles on it and runs great at all speeds but idle. It gets a consistant 13 mpg. This weekend I am going to change the intake gasket. I am getting these codes P1171,P1174,P0171,P0174, P0102 MAF signal minimum threshold, and a P0505 blocked Idle Air Control Valve. I cleaned the IACV with carb cleaner. It looks like I am due for some new plug wires. About a week ago I was very low on gas at home so I put a gallon of 87 octane in to get me to the gas station, Maybe that caused a problem. I alway run 92 octane normally.

Head gaskets 50,000 miles
valve job 50,000 miles
Bosch +4 30,000 miles
Magnacore 8mm 104,000 miles

Thank you,
Willie

 

My last code reading is showing a

P0300 random misfire
p0301 Misfire Cyl 1
p0302 misfire cyl 2
po304 misfire cyl 4
po306 misfire cyl 6
po307 misfire cyl 7
po308 misfire cyl 8
po171 too lean bank 1
po174 too lean bank 2
p1171
p1174

The reading before that showed misfires in all the odd cylinders only. Could this be a problem with the coils? The Idling problem started instantly not gradually.

Thank you,
Willie
2000 DIscovery II