Question about Lexus LS 400

1 Answer

I swapped out the plug wires and plugs with Denso, while I had the covers off decided to wash engine, engine ran fine. Next day started engine and the idle constantly oscillated between 1200 to 1400 RPM. If I disconnect the MAF the oscillation stops, but engine runs rough... Most folks say its almost never the MAF, looking for any ideas...

Posted by on

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 766 Answers

You are right this is a classic MAF problem or rather the air mass meter AMM which is the MAF working with the closely associated intake air temperature sensor IAT(a little bead like thermistor on wire sitting close to the MAFF in the air stream). The ECU was getting poor information from the MAF. The ECU had to rely on slow input signals from the IAT and feedback from the oxygen sensor on the exhaust to keep the engine running. The ECU hunted for the right mix, first rich and then lean but never settling hence the 'surge and slow' of the engine revs. When you disconnected the MAF you also disconnected the IAT and now the ECU had just the one signal from the oxygen sensor to depend on and so now provides a slightly rich mix giving the rough idle. You have done the hard work just change the MAF and IAT assembly.

Posted on Aug 19, 2010

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

I have a 94 ford ranger, 4 cylinder 8 spark plugs, 150 thousand on it, the vehicle has ran flawlessly until a week ago, the first sign was driving down the road it started skipping and had a huge loss of...


Two plugs per cylinder? Just wondering why it has twice as many plugs as it does cylinders.

Anywho; have you tried fresh wires, or at least swapping them around?

Nov 28, 2014 | Cars & Trucks

1 Answer

Here's my problem, 99 Subaru Legacy 2.5 dohc. I


in order to replace the cam seal you have to remove timing belt if tou did not have this problem before you have one skipped thoot on your subaro box engine recheck your timing again

Oct 18, 2014 | 1999 Subaru Legacy

1 Answer

I sprayed engine cleaner on engine, and i thought that i carfully rinsed of the engine. The car started and ran fine for the next two days. NOW the car will not start. The engine turns over fine. But i...


ok if the car ran after it got wet then its not the problem engines can get wet and be fine sure thats not the problem they burn of the water anyway check the plugs and see if fowled out and check wires for cracks if older wires when you got them wet they might have got hot then cold then cracked from age check and see if they need replaced hope this helps

Sep 16, 2010 | 1988 Chevrolet Celebrity

1 Answer

Subaru Legacy 1995, will not start. Battery is fine, replaced battery connections; fuel filter, spark plugs and wires about 1 year old. Engine turns over and over, and over, just can't get it to ''fire,''...


was the check engine light on? have it scanned for a code if it was. remove the timing cover just enough to peek and just make sure the timing belt isnt broken. do you smell gas coming out of the exhaust while cranking the engine for 10 seconds? if not it could be gas related. or pull one of the plug wires off a spark plug and hold it a 1/4 inch or a little less away from the engine ground (ANY METAL PART OF THE ENGINE)see if it archs while cranking for 5 seconds, if it does not arch suspect that the camm and or crank sensor is a bad. PLEASE NOTE: this information is based on what you have told me. however if you have it scanned and give me the code pulled i will be better equipped to help you. if u run the tests i gave you and come up with nothing you may have to take it to your local technician for more complex tests to be done.

Jul 21, 2010 | 1995 Subaru Legacy

1 Answer

WILL NOT START


sounds like water ingress to either a control module or the coil pack, check all control box locations eg footwells for water and then check the engine bay for loose or naked wires, dry and clean and possibly cover with a plastic bag etc and it should be fine.

Jun 14, 2009 | 2000 GMC Safari

3 Answers

Engine wont start


if you can hear the fuel pump when turn the key on with out turning the engine, then it could be that your fuel pressure regulator is broken, check your fuel pressur.

Jun 12, 2009 | 1993 Chevrolet Astro

2 Answers

Put new glow plugs in ran fine for 1 day now it wont start..


You may want to surf around on some of the powerstroke forums for detailed answers, but I know the powerstrokes use oil pressure to control the injectors so you may have some problems with the high pressure oil pump.
Again, it is just a guess. I just wanted to point you to some of the Ford Powerstroke forums which may be of much more help for you.
Good luck..

Feb 02, 2009 | 1997 Ford F350 Crew Cab

1 Answer

2000 MX-5 Miata Misfireing


you are showing the classic symptoms of a failed coil pack. I think you can get one for about $230 from rosenthal mazda (finishline performance)

Aug 09, 2008 | 1999 Mazda MX-5 Miata

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

296 people viewed this question

Ask a Question

Usually answered in minutes!

Top Lexus Experts

yadayada
yadayada

Level 3 Expert

75822 Answers

ROBERT GARCIA
ROBERT GARCIA

Level 3 Expert

881 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22156 Answers

Are you a Lexus Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...