Idle problems again...drops to 400 and is real rough... (1 Viewer)

[Arya Ebrahimi]

Just about to leave for the drive home and then on to Hatteras tonight and the cruiser starts acting up....

It's been hesitating slightly off idle for a few weeks now, but usually only when it's cold. All of a sudden now I came back from the store and put it in park and it drops down to 400rpm and is idleing fairly roughly. Enough that you can feel it in the cab with it in park/neutral and you can see the rear edge of the hood vibrating noticeably.

All within the past 10k miles/since November:
belts
O2's
vacuum hoses(all of them)
cleaned TB/intake
tuneup(plugs/wires/cap/rotor)

I'm going to be doing about 1500 miles worth of driving in the next week, so this is a bit disheartening. I'm overdue for an oil change, and will be doing it this afternoon, but I doubt that would have any effect on the idle.

BTW, it's consuming 1QT of Mobil 1 every 1500ish miles. It's burning some and leaking some. Truck smells like a two-stroke...

Suggestions?

Ary

P.S. Dunno if it matters, but Voltage, Oil Pressure, and Temp are all reading in their proper ranges...

 

[IdahoDoug]

Check the intake rubber tube's pleated section for cracks on the bottom where you can't see them unless you remove it.

DougM

 

[Arya Ebrahimi]

Good idea Doug, will check that momentarily. It would make sense since it's an intermittent problem. Just ran over to a friends house and it was fine the whole way there and back.

Ary

 

[Scamper]

Check/replace your PCV valve too. That could be where all your oil is going.

 

[green_machine]

do a leak down and compression test.

 

[JAPFPE]

Arya,

Very ironic post since my LX450 thru the Check Engine Light (CEL) while in Hatteras last week. Anyway, we had an event free trip down and back to Syracuse, NY but did notice the truck was idling very rough while at the Hatteras Marina (off-shore fishing trip got blown-out...surf fishing for Blues was awesome though !). I traced my problems to a pretty large exhaust leak just forward of the muffler at the O2 sensor. I did clean the throttle body using some Valvoline Throttle Body and Carb cleaner which seems to have improved the idle greatly. The throttle body was caked with crap inside and the butterfly valve was pretty gunked also. I did not remove the T/B but rather removed the intake hose and gagged the butterfly open before blasting it with the cleaner.

 

[CruisinGA]

I have had the same problem intermittently since I bought the truck.

It almost never completely stalls out, and hence I have not worried about it.

Tomorrow I am cleaning the throttle body, and I am hoping this will help with the off-idle issues. I may also run a layer of duct tape around the intake hose to eliminate that as a cause.

If I find anything that may be of interest, I'll post up Ary.

 

[Vitesse_6]

Mine has done this, I cleaned the TB and all went great for about 5 months, Then its dead ass winter and starts acting up, It did it for about a day, Then all was right in the world, I did read something about the computer readjusts something, It takes a few ign. on/off seq. to right its self. I dont know if this might be the same issue or not, The few times it did it I changed Alt. +/- a few 1000 feet.
Good luck