Land Rover Forums - Land Rover Enthusiast Forum - High Cold Start RPM with Rough Idle

Land Rover Forums - Land Rover Enthusiast Forum (https://landroverforums.com/forum/)

- LR3 (https://landroverforums.com/forum/lr3-28/)

- - High Cold Start RPM with Rough Idle (https://landroverforums.com/forum/lr3-28/high-cold-start-rpm-rough-idle-92486/)

High Cold Start RPM with Rough Idle

Hey all,

I've got a 2008 Land Rover LR3 with 143,500 miles on it. Two days ago the car ran great! I went to start it yesterday and the RPM's jumped up extremely high to about 3,000 RPM's as soon as I turned the car on and then dropped well below 1,000 RPM's after, as I let the car warm up. The RPM's continued to fluctuate between 100-750. During this time the car was smoking out of the exhaust as the RPM's dropped to it's lowest point and the truck felt like it was going to die out. I've attached a link to something I've found on youtube that is pretty similar to what I was experiencing. I've kept up with all preventative maintenance, recently cleaned the throttle body, oil looks great, air filter is changed regularly. From what I've read it could be the Mass Air Flow sensor or something really simple... but I haven't gotten the reduced engine performance or anything lights come up on my dash. Has anyone experienced something similar? I haven't had much time to do any more investigating due to my work schedule, but wanted to touch base here before having it towed to a shop.

Reference Videos:

Thanks all!
Matt

MAF, thermostat, ignition coil...usual suspects. Or wiring issues due to water ingress or....wait for it....MICE!

My first though is PCV valve. Easy to replace, not horribly expensive. And they are known to fail.

edit:
A thread I found
https://landroverforums.com/forum/lr...our-pcv-77798/

Thank you guys for your help! MAF cleaner, PCV Valve and new spark plugs are on their way. Going to test the ignition coils as well. Appreciate all of your help, I'll let you know how it goes!

Yes, PLEASE update. Nothing worse than threads that fall dark and then in 6 years someone resurrects it with "Hey, I have the same issue. Did you ever figure it out?". :D We have ALL seen those! lol

I replaced the PCV Valve, cleaned the MAF sensor thoroughly, replaced the air filter and put some 44K Fuel Cleaner in the tank. It ran rough initially, but then I drove it for a few miles. Ran great until the Check Engine Light came on followed by the Engine Fault System message on the information center. After those pupped up I pulled off the road and the car felt quite sluggish. I pulled over and let the car sit for about 20 minutes. While it sat I popped the hood and checked the new PCV Valve and the rest of my connections. Everything checked out and I started it back up. Everything ran smoothly from that point on, but my check engine light is still on. I’ve driven it a few times today down the street and around the neighborhood. Idle is smooth, but still some faint white smoke after the car has been warmed up. It’s about 45 degrees outside so not terribly cold... from what I’ve read should I be checking the heads? I’m planning to do the spark plugs tomorrow... thanks all!

Rough idle on start up 2008 LR3 4.4 V8 HSE

Well I replaced the spark plugs and everything was going well, except for I broke the PVC hose (brittle). I had a very bad idle until I duct taped the PVC hose together until a new one arrived. All was good. Then decided to clean the TB and MAS. Every thing went great. Put everything back together, but... rough idle on start up, and stalling again. Tried to pull any codes. Nothing. Finally popped the hood again had a look at the connectors at that the throttle body, MAS, all good. ? Then I saw that when I was putting the engine top cover back on I forgot to replace the oil cap on the filler.
Everything was fine after that.
Point is start with the basics and check everything is properly connected.