Random Misfire at idle - Land Rover Forums : Land Rover and Range Rover Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 31 (permalink) Old 12-22-2009, 09:25 AM Thread Starter
Member
 
Join Date: Jul 2009
Posts: 52
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Random Misfire at idle

I bought a 04 Land Rover disco about 6 months ago and had done a lot of work on it: Head gaskets, cam shaft, timing chain, rods, lifters etc...

One problem I've been struggling to fix is that at idle the engine has random multiple misfires. If I give it some gas, it stops misfiring. This happens when the engine is cold or hot. If I get off the highway and am at a red light, it can happen. It's very random.

I tried troubleshooting it as a vacuum leak, but didn't have any luck there.

Some things to note:
New coil pack
New Wires
New Plugs

It runs fine, it just has trouble at idle.

Any ideas?
locke547 is offline  
Sponsored Links
Advertisement
 
post #2 of 31 (permalink) Old 12-22-2009, 09:32 AM
Senior Member
 
nasa25's Avatar
 
Join Date: Mar 2008
Location: Toronto, Canada
Posts: 891
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
how old is the air filter?
what about maf?
what grade fuel are you using?
what type of plugs?
what type of wires?
nasa25 is offline  
post #3 of 31 (permalink) Old 12-22-2009, 09:35 AM Thread Starter
Member
 
Join Date: Jul 2009
Posts: 52
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
how old is the air filter? - Pretty new
what about maf? - It's plugged in, what else to know here?
what grade fuel are you using? - 93
what type of plugs? Bosch
what type of wires? Bosch
locke547 is offline  
post #4 of 31 (permalink) Old 12-22-2009, 09:35 AM
Senior Member
 
listerdiesel's Avatar
 
Join Date: Nov 2009
Location: Rushden, Northants
Posts: 513
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Also, check the idle control valve is free and the hoses tight, and the vacuum connection for the brake servo is good.

Peter
listerdiesel is offline  
post #5 of 31 (permalink) Old 12-22-2009, 09:37 AM Thread Starter
Member
 
Join Date: Jul 2009
Posts: 52
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Those are actually the 2 last things I checked, thats what I was thinking it was.
locke547 is offline  
post #6 of 31 (permalink) Old 12-22-2009, 10:40 AM
Senior Member
 
DiscoDream2's Avatar
 
Join Date: Sep 2009
Location: Summit County - CO
Posts: 3,218
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Any lights lit up on the dash? Did you check for fault codes with a scanner?

DiscoDream2 is offline  
post #7 of 31 (permalink) Old 12-22-2009, 11:40 AM Thread Starter
Member
 
Join Date: Jul 2009
Posts: 52
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
When it misfires the Check Engine light flashes. I let someone borrow my scanner, so I don't have it at this time, but I was getting random misfire codes before when I checked.
locke547 is offline  
post #8 of 31 (permalink) Old 12-22-2009, 11:54 AM
Senior Member
 
DiscoDream2's Avatar
 
Join Date: Sep 2009
Location: Summit County - CO
Posts: 3,218
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Go to the ZOne and they will read them for free if you can...

The "maybe" list will start with:
Wires
plugs
mafs
coil
gas
See a trend!

What are the brands you used to replace wires etc?

How has the coolant level been? Any funny smells out the tail pipe?

How many miles, last tune up, have you looked at the plugs lately?

I went through three sets of wires till I got it right, then the MAFS went, just after the HG's were replaced, which was just after the alternator went with the battery, the coil was replaced by throwing parts at it, just before the throttle body gasket started to erupt, the PAS pump still leaks and hard to turn after replacing it, the HDC light comes on randomly and the sunroofs leak like a B when the snow melts and right around the time we replaced the fuel pump thinking the hesitation was lack of fuel, but it turned out to be bad plugs for the third time trying to save a buck or two on plugs. ;-)

Need more data / fault codes really.

DiscoDream2 is offline  
post #9 of 31 (permalink) Old 12-22-2009, 10:59 PM
Senior Member
 
listerdiesel's Avatar
 
Join Date: Nov 2009
Location: Rushden, Northants
Posts: 513
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I'd have thought that the MAF (Mass Airflow sensor) could be eliminated if the truck runs OK otherwise, same with the plugs and leads.

The SAI (Secondary Air Injection) system might be worth looking over, especially as there is a vacuum connection between the vacuum reservoir and the inlet manifold. The system normally only works at cold start.

Lastly, there is the charcoal canister purge valve on the driver's side of the upper inlet manifold, and while you're there, run a spanner/socket over the bolts holding the plenum onto the manifold and those holding the whole thing down to the manifold.

Peter
listerdiesel is offline  
post #10 of 31 (permalink) Old 12-23-2009, 08:21 AM
Senior Member
 
Join Date: Sep 2004
Location: Churubusco, IN
Posts: 4,696
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Pitch the Bosch plugs and get some Champion 318s.

Yes, I am still alive, and still in the Rover parts business.
Text me for greatest likelihood of finding me.

260-804-0458

Dominic Perodeau/Global British is a thieving bastard, do not send him money.
PTSchram is offline  
post #11 of 31 (permalink) Old 12-23-2009, 08:33 AM Thread Starter
Member
 
Join Date: Jul 2009
Posts: 52
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
So I had 1 side of the SAI disconnected because I needed a new SAI plug. I've got that and I'm gonna throw that on today to see if that is contributing.
locke547 is offline  
post #12 of 31 (permalink) Old 12-23-2009, 09:52 AM
Senior Member
 
Elemental's Avatar
 
Join Date: Feb 2007
Posts: 4,408
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
First - A flashing ses light means the cats are melting internally. Its smart to shut it off when that happens.

Second - Bosch plugs are shit. I would bet both of my testicles that when you put in the right plugs, your problem will be solved.
Elemental is offline  
post #13 of 31 (permalink) Old 12-23-2009, 11:00 AM
Senior Member
 
DiscoDream2's Avatar
 
Join Date: Sep 2009
Location: Summit County - CO
Posts: 3,218
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Elemental View Post
First - A flashing ses light means the cats are melting internally. Its smart to shut it off when that happens.

Second - Bosch plugs are shit. I would bet both of my testicles that when you put in the right plugs, your problem will be solved.
Echo that! E

DiscoDream2 is offline  
post #14 of 31 (permalink) Old 12-24-2009, 05:44 AM
Senior Member
 
Join Date: Sep 2004
Location: Churubusco, IN
Posts: 4,696
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Elemental View Post
First - A flashing ses light means the cats are melting internally. Its smart to shut it off when that happens.

Second - Bosch plugs are shit. I would bet both of my testicles that when you put in the right plugs, your problem will be solved.
It's easy to suggest something when it was introduced two posts before

Yes, I am still alive, and still in the Rover parts business.
Text me for greatest likelihood of finding me.

260-804-0458

Dominic Perodeau/Global British is a thieving bastard, do not send him money.
PTSchram is offline  
post #15 of 31 (permalink) Old 01-31-2010, 06:16 PM Thread Starter
Member
 
Join Date: Jul 2009
Posts: 52
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
So I replaced the plugs with the OEM plugs, and same thing... What the heck?!
locke547 is offline  
Sponsored Links
Advertisement
 
Reply

  Land Rover Forums : Land Rover and Range Rover Forum > Land Rover Model Forums > Discovery Series II

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Land Rover Forums : Land Rover and Range Rover Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Idle Control Valve - idle problems; get to know it glenncof Range Rover Classic 4 01-20-2014 10:38 AM
base idle adjustment?? stalling, idle issue bothfeetin Discovery Series I 0 05-20-2008 05:38 PM
Poor idle after warm weather restart...misfire riemer Discovery Series I 0 01-27-2007 06:12 AM
96 disco idle, misfire problems!!!!!! cbrown12 Discovery Series I 12 06-07-2005 05:20 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome