I have some ideas on what to check, but would like some feedback if anyone can think of something else.

I was out in the garage working today and flushed/replaced the coolant and replaced my CDL switch. I idled it fine pin the garage for a while 10 min or so afterwards with no problem, I also drove it around the block with no problems after the CD switch, but before the coolant flush.

I drove 3 miles or so to Auto one to pick up a coolant test kit to check the temperature rating of my mixture. The vehicle ran absolutely fine on the way there. I picked up some new parking lights and put them in I. The parking lot. N the way home I went on the freeway this time and as soon as I got off it was misfiring really bad at the redlight and shortly after the engine light was flashing constantly. I have an obdii scanner hooked up and was looking at the live data.

Very lean voltages on other O2 sensors
The load was abnormally high for idle 16-20%
Maf sensor seemed to be reading fine

I kow not recommended but I limped it 1 mile home. I had to put it in low gear to help it out with moving as there was no power because of the misfires.

Thns to check:
1. Vacuum leak, I would imagine one big enough to cause this woud be audible, but I'll check again.
2. Fuel pressure; pump or clogged filter

That's all I got. The misfires were on 1, 4, 6, and 7. These are all on one coil, but if they were misfiring froma coil I would expect to see rich on the O2 sensors from unignited gas.

Anything I'm overlooking?

 

What year, how many miles on it, when was it last tuned , what octane and the important one what are the fault control numbers?

 

Mike,

91k miles. It has the blue sti wires on that were put on this Feb by the PO. I put new plugs in it not too long ago ~2k miles. O2 Sensors were replaced <500 miles ago; MAF was replaced ~151 miles ago. When i bought this thing it had a lot of problems from neglect and I'm slowly sorting them out. The last 150 miles have been really nice until now.

I went out and idled it in the garage this morning.

-The O2's show realy low voltage if I rev it up, but at idle they are around .7 and will randomly drop to really low. They arent' switching between high/low like normal. Nor do they mirror each other at all.
-MAF is showing what I'd expect at idle. I believe it's around 6 gallons
-Last night the cats started smelling horrible
-I found the gas door open and cap slightly loose this morning (I have a 1/2 tank and wouldn't have touched this and it's been closed)
-When idling the garage straight up smelled like my 65 Plymouth idling rich
-Vacuum was sitting at ~14; if I raised the revs it would go up a little (22-23) then go back to 14

-Since it's a Disco; the coolant temps always sit around 203 on the scanner


It's making me think that maybe that coil has taken a crap. I guess 2 out of 4 cylinders on each bank not firing would mess with the fueling pretty bad. 4 cylinders not ingiting could explain the rich smell and cat burning egg smell from the raw fuel. I guess the O2's would sense this and that could prompt the computer to adjust fuel trims to correct the "rich" condition and then run lean. Just a thought. I'll work on it this afternoon.

 

P0300 - Random Multiple Misfire
P0301 - Cylinder 1 Misfire
P0304 - Cylinder 1 Misfire
P0306 - Cylinder 1 Misfire
P0307 - Cylinder 1 Misfire
P1590 - Three amigos

 

Have you checked electrical connections?



PASS SIDE DRIVER SIDE coil packs

8 5 6 1
2 3 4 7

 

Took a minute to get back to, had to take our 4Runner in for dealer servicing and subsequently wasted 1.5hrs looking at vehicles we can't afford in the meantime. Stopped at Harbor Freight on the way home and picked up an Inline spark tester. Showed weak spark on 4 and 6, didn't bother checking the other bank. Was a loose connector n the driver side coil I couldn't get my hand in the small space so I enlisted the wife and her small hands. Took her longer to change than to fix it; I would have had to remove the top of the intake.

 

It sounded like a loose connection to me not a bad coil!
Good job!
Merry Christmas

 

She's a keeper! Good work man.

 

I think this could go on the calendar shoot for the mechanics...