I still wouldn't rule out the cats. Typically if they are getting plugged up the misfires and rough running won't manifest itself until higher rpms, but it might still be worth a shot to disconnect the exhaust.

 

Quartz

Is it relatively easy?

Up on jack stands, and a few bolts and flanges?

At this point, I'm kinda at a loss.

I wonder where a guy would start, if he came to the car with this issue - not knowing the history.

On my list is still
1) Massive air leak of some type
2) Something misconnected/not connected/poorly connected mis-installed
3) Anything that could cause an electrical gremlin - broken wires, corroded contacts

feels like a losing battle

 

jar I PM'd you.

 

So, as I think on this, I come back to step 28 as well - see the attached.

Is this referring to an actual "ground strap"? What I would typically think of as a wire lead, with ring terminals, bolted down to something?

I don't believe we ever saw anything of such nature when going thru this ordeal. We took the "strap" description to mean the bracket that holds the air intake elbow.....

Anybody familiar with this area or this item?

Clarity here would proally be a good thing, as it feels like I'm chasing ground/electircal issues......

Kind Regards

 

You don't have to pull the whole exhaust out, just unbolt the exhaust right above the cats so there is a gap between the headers and the cats. It should be relatively easy unless there is a lot of rust.

 

Clogged OEM cat caused misfires on my 2005 STR. I did not have failure codes for cats but did have multiple misfire codes and specific pluge code misfires. I will find the link and place it here for you shortly...


<Update>
See post #22 and here's the link...https://www.jaguarforums.com/forum/s...g-56188/page2/

 

Since jar hasn't posted his fix.

It turned out to be a small crack in the intake tube.

 

Sorry to not have gotten back - wanted to wait until I had it completely sorted.

As Joyce indicates main source of drivability issues (all the misfire codes), was an intake leak at the pcv hose, under the TB motor. We capped it, and let the pcv valve vent to atmosphere, and the engine ran reasonably well.

With engine at least running now, I ordered a new PcV valve and hose, and installed those this weekend (3/25).

Again, engine runs well - but now I have a new set of codes to chase.

Thanks all for the help, and ideas were much appreciated.

kind regards,

joe