Well, my 98 Disco seemed to be running fine until one day I notice while warmed up the engine seemed to be running rough at idle, missing and stumbling. The problem only became worse. First it only occured if the vehicle was driven over an hour, now it occurs whenever the vehicle is warm (within 5 mins of start up) but when cold it seems to be fine.

I checked with a timing light to see if there was an obvious misfiring cylinder however they all seemed to be firing. I did notice that the rate of speed of the timing light on all the driver side cylinders seemed to be double the speed of the flashing on the passenger side wires.....

Replaced plugs since the ones in their appeared to be older than dirt, but to no avail, doesnt run any better.

Hoooked up my scanner and got the following codes

P 0203 injector circuit open cyl. 3
P 0300 multiple cyl. misfire
P 0303 misfire cyl. 3
P 0304 misfire cyl. 4
P 0306 misfire cyl. 6

P 1203
P 1316
P 1314

new NGK plugs and bosch wires last night. didnt help

I have been doing research and found that some possibilities are the coil packs as well as possibly the VSS. The VSS will be a simple test (just un plug it) however the coil pack is a different story, any ideas on how to test it>?

Compression good all around

Any suggestions would be tremendous, as my wife doesnt like it when I drive her car...................and the dealer will put me in the poor house.

THANKS

 

Well you are going to need to change those plug wires.
You need to use Magnecor plug wires as these trucks are picky.
www.apexperformance.net has the best price on them.
Your plugs are fine though.

If you unplug the VSS it wont run.

The GEMS engine sparks on every compression stroke.

What grade and brand of gas are you using?

 

i use 93 octane. usually name brand fuel. After work came home and got right into the disco. First I got out my scanner and cleared out the existing codes. Then started it up and went for a ride. To my surprise it ran perfectly.

great idle

nice accelleration

no hessitation or sputtering

unfourtunatly it only lasted about 10 mins. once fully warmed up it began to shudder at 75mph. then became worse. slowed down and i had the rough idle, the obvious missing on accelleration and just sounded like crap.

Im sure that there isnt anything damaged like the coil packs or wires or valves and such since it runs fine until it warms up then it just craps out.............

any ideas

 

If you start it when cold and let it idle in the driveway once it gets hot will it idle rough?
Or does it only start when driving and then continue from there?

 

started it up this morning before work. 22 degrees F and it idled real smooth around 1k. after 5 mins it was running smooth at about 700 to 800. came back 10 mins later and it was already stumbling when giving it gas.

anything , any ideas?

 

You need to deal with your injector issue which is causing the majority of you codes.
Along with Spike, I would question the plugs and wires, those Bosch wires are not known to hold up long and will throw codes.

 

to check the wires open the hood and run the truck in the dark.
look for the fireflies when it starts stumbling.
you may also want to spray a fine water mist onto the wires if you dont see anything when its stumbling.
use a mirror to view the coilpacks

 

well, tonight when I get home I will take a look at the injector issue. Hopefully its just a problem with the wiring.

I just dont understand why it works when its cold but not when its hot. Does it have something to do with open / closed loop ?

 

Just to clarify the truck had a set of STI wires originally. After I noticed the problem I switched to bosch and new plugs. I didnt know that the brand of wires matteredso much or I wouldnt have bought them......

 

I don't think it has a stinkin' thing to do with your wires. Driveability problems like these usually require the need for a decent scanner that allows you to see how sensors are operating. Yes I would definitly think it has something to do with being in closed loop. Is it running rich? Can your scanner tell you when it is in closed loop or open loop?

How many miles on this one?