Hey folks,

Got in the truck this morning on a cold rainy day in the Bay, and to my surprise the disco was idling rough. Plugged in my code reader and got the codes aforementioned. I had just switched from 89 to 91 octane gasoline a few days ago. Up until this time I had one other instance of rough idling when I first bought the truck and we saw that the PCM just needed more grounding and it fixed my misfiring.

But kind of clueless as to what could be the issue here. Any ideas? Thanks in advance.

 

Have you searched Workshop Manual PDF for each individual code yet? Only takes a couple of minutes, code descriptions appear as well as some clues.

This one doesn't sound too good.
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could be the weather. could be the change in octane and the computer and related systems trying to adjust to that. could be something else...

 

Haven't had a chance to parse through each code individually. I will do that tonight once I'm off work to see. There's an esteemed British automotive specialist down the street from where I live, was thinking of popping it over there and seeing what they make of the codes.

 

Are the spark plug wires pretty old? I am of the opinion that moisture got into an electrical connection. Could be anything, anywhere. I had the same problem, same scenario once, awhile back. After the the 2nd day, it cleared up on its own and has never happened again. I replaced a bunch of stuff as preventative maintenance and tune-up, but never did lube the ECU and harness connections as I was so advised in my thread that I posted about the same problem. Others responded that applying dielectric or waterproof grease on the connections was a fix for the rough-running Rover V8 in changing weather conditions

 

The spark plugs and the plug wires are pretty new actually. I suspect, as you said, some moisture got into an electrical connection. I have been doing some rovering in some mud and it's been raining here for the last month. Makes perfect sense.

And wouldn't you know it, darn SES light actually turned off last night on the drive home. So when I got home, to be sure, I plugged in my code reader again and still got codes. But was wondering if these codes are residual from earlier? They're the same type as I saw earlier, carbon copy.

 

I don't know but if it idles at stop lights and isn't misfiring I would keep on clearing the codes and driving it for a couple of more days until the sun comes out and dries things up. open the hood for a couple hours when it does so and then see what happens

 

The 1415 is SAI flow related. Usually seen along with 1412.

Fix is often vacuum tubes leaking, spigot cracked somewhere or SAI solonoid busted.

That's an odd combination, in my mind.

 

Agree to look closely at your SAI vacuum lines. Have had multiple or singular SAI codes with SES. Lines are plastic tubing with rubber nipples which may soften from oil then slip off and are easy to knock off doing other mx. Such vacuum/intake leak can also cause other issues such as higher than normal/spec idle.

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Thanks all for replies. I'll take a look under the hood today and check vacuum lines. I've had a few codes related to SAI lately but that had been happening without misfiring. It only a few days ago started misfiring.

I'll take a looksie and report back. Thanks for all the insights