Hey everyone, so long story short I took a trip two weeks ago through some CO mountain roads after replacing my Thermostat with a 180 soft spring and m'laday finally did not heat up on those passes. Yay!

However on the way home as I was passing someone I noticed a drop in power and then I noticed my check engine light came on and was flashing at me. It would flash mostly when I was accelerating.

The acceleration felt very underpowered. So I know a flashing light is never a good sign but what you gonna do... Gotta get the family home somehow...

Anyways I start hitting those mountain roads again on the way home and I said a prayer as I held the pedal on the floor looking for any extra power to get me over those passes.

She was pushing hard. That engine was running 4.5k to 5k RPM for a good long clime a couple of times. (IT didn't heat up though so one problem fixed with the Tstat)

Once I got her the hills it would smooth out a bit but again accelerating would cause the light to flash and power loss.

So she made it home. She felt very rough once i got into the city and was in the low speeds and RPMs. It felt like it would stall out if I didn't keep a little pressure on the gas.


So I took her in to get the codes read and she spat out a nice list

p1300
p0303 - cylinder 3
p0305 - cylinder 5
p0307 - cylinder 7
p0300 - multiple missfire
p0301 - cylinder 1
p0134 - o2 circuit no activity ( i just did my 02's a month ago )
p0172 - Bank 1 system to rich
p0603 - Internal contro module


So... I know there can be a chain reaction that can cause many systems to go haywire.

What I am thinking is I am going to replace the coil pack ignition cables and spark plugs.

Since I will be doing that what I would like to know if you guys think I should do a few more things while I am at it? Or just get get up and running again?

Thanks!

 

valve cover gaskets. new throttle body pre-heater assembly if you haven't bypassed it already.

 

Uhh, what?

 

Before you worry too much about taking everything apart to check the coils. Chubbs may be right. If your bank 1 valve cover is leaking it could be dripping oil onto the O2 plug which could be why it's showing no reading and would explain why all the misfires are on one side. I would tighten the outside bolts on the valve cover gaskets and check/clean the plug with electircal contact cleaner. Clear the codes and try it out. If that doesn't work, I'd switch the O2 sensors between banks to see if the miss moves from one side or the other. If it does, replace your front O2 sensors with new Bosch sensors. They're about $55 each on amazon and I prefer to do both banks at the same time.

I doubt its coils or plugs since its only on one side but its all of that side at once. Very unlikely.

 

Wow now that is some wise insight right there. I will take a look tonight and report back. The 02 sensors I have right now are the same BOSCH ones from Amazon.

If I don't see oil on the 02 should I still try switching the 02's around? Seems like a good first step before dropping some $$

thanks

 

12 pt 8mm 1/4 drive socket for the valve cover gasket

 

I would still try swapping them even if there's no oil. It's always possible that something happened to the sensor itself and this is a good free diagnostic tool to find that out.

 

Yep.

A well known, frequent contributor on this forum who's no longer around swore up and down that a bad O2 can't cause misfires, at least not without also throwing O2 codes, but that's exactly what happened with my truck a couple of years ago.

 

Alex_M and everyone else THANK YOU!!!! You just saved me a good amount of time and money.

I finally found some time to play with the disco. I started inspecting the engine bay and sure enough where all the misfires are happening that drive side of the engine is all covered in oil.

I pulled the to front o2s they did have a dark ring around them i cleaned it off and placed the o2s back but flipped the left to right and right to left.

I pulled the spark plug cables from he driver side and cleaned them off and inspected the connection. There was a bit of oil/dirt on them.

Topped her back up with oil and fired her up. She smoked for a little not a lot smoke but enough to notice. I let her warm up and then went for a drive and she felt great.

I cleared the codes and went for a hard ride pushing the RPM's and so far no new codes have come up.


So I thank you for that information it really showed me to look and diagnose a problem in a much better way then to start replacing parts.

 

thanks for that info as well. I will get those nice and tight tonight