Pipes not pushed fully home on the valve block?

But if you did read from the beginning, or even from halfway through, you'd see that if he plugs the SAI pipe with his finger it runs normally...... Definitely a problem with the SAI system rather than anything else.

Do you have any diagnostics James? As you've found, the temperature sensor on the Thor is two sensors in one body (rather than 2 separate sensors on the GEMS). One feeds the dashboard temperature gauge while the other feeds the ECM. If you connect OBD diagnostics that can display live data and look at what engine temperature is shown. If it is obviously wrong, that is the problem.

Unless your lower grade fuel is really poor, a P38 doesn't need top grade stuff. Recommended fuel is 95 RON which equates to 90 in the US as a different method of grading is used (AKI or (R+M)/2).

As it appears to be an SAI problem, there is limited knowledge here to help as only NAS cars had it fitted. Reading about it in RAVE, it appears that it should only operate on a cold start and not a hot start so it could be caused by a temperature sensor problem. I understand on later NAS cars, there is an additional one in the radiator, presumably earlier ones just used the engine sensor.

RAVE says:

The engine control module (ECM) checks the engine coolant temperature when the engine is started, and if it is below 55°C (131°F), the SAI pump is started. Secondary air injection will remain operational for a period controlled by the ECM and is dependent on the starting temperature of the engine. This varies from approximately 95 seconds for a start temperature of 8°C (46°F) to 30 seconds for a start temperature of 55°C (131°F). The SAI pump operation can be cut short due to excessive engine speed or load.

As it's operating a solenoid, I would suspect at a pretty low frequency or it wouldn't get chance to operate before it released. Then again, I would expect the SAI to operate for a set time rather than being pulsed.

I've got a spare UK Thor ECU..... You only need the Nanocom to copy and paste the initialisation code from ECU to BeCM.

@LPGC, no it isn't a PWM signal, it is a permanent live directly from the fuse (via a splice) with the ground,either permanent or pulsed supplied from the ECU. So provided he is testing the voltage with respect to ground and not across the pins, it should show full battery voltage.

If the SAI isn't needed to pass emissions in your particular US State, then it can be removed. All you need to find is some blanking plugs to blank the holes in the cylinder heads. Once they are blanked the rest can be taken out and removed. Not sure if that will throw a fault code or not though. If you disconnect it and check for any SAI related codes you may have to put a resistor in place of the solenoid to fool the ECU. The purge valve is a separate system and even on a UK car if that is disconnected you will get a code thrown.

Ground is supplied by the engine ECU. They both share the same supply from fuse 26 which also feeds the MAF, ECU box fan, O2 sensors and cam position sensor on a Brown/Pink wire. See pages A1, page 4 for a description of how it works and A1 pages 8 and 15 in the ETM for the relevant bits.

Dodgy connection somewhere.....

Can't you just plug the pipe and leave it at that? The rest of the world survives quite well without any of the SAI stuff.

Doesn't does it. I tried to edit your post so the picture appears but don't seem able to do it, so there's a click-able link now instead so others can see it. Moisture gets under the insulation and rots the copper so you end up with a high resistance or no connection at all.

Mine would do that a couple of years ago. I found that if I switched off and restarted, it was fine. One day I had the Nanocom plugged in and checked for any stored codes and found one for the EVAP solenoid. Had a look at it and noticed one of the wires had corroded and pulled out of the plug. Found a suitable plug, soldered it to what was left of the wires into the old one and it hasn't done it since.

From what I've found online, it could be down to a dead SAI pump but I don't really know enough about it as it is an NAS only feature.

Misfires will be as a result of running rough, so the only one that points to the actual fault will be the SAI code. It decodes to P0413 OBD-II Trouble Code: Secondary Air Injection System Switching Valve A Circuit Open so that is where you need to be looking.

Hmm, yes, not completely knackered but not brilliant.

Look at them for any wear or scoring where the rockers will sit and check there's no slack on the rockers themselves on the shaft. If there is no noticeable wear, they should be fine.

As you have found out, you do need a tapered tool to press the bushes into the suspension arms, but you shouldn't need one for Panhard rods. Clean up the hole, put the bushes in the freezer and just press them in with a hydraulic press. It's amazing how much difference it makes taking all the slack out from the front end.

How does this compare? http://www.ecolambda.co.uk/main/ecosale/price.pl?item=250-24804

As Pete says, we drive on the left so the right hand is free to use the sword on someone coming the other way. Unfortunately Napoleon was left handed, and didn't much care for us Brits, so he insisted that the French drove their horses on the right. Rather than keep swapping from one side of the road to the other when you crossed the border into another country, the rest had to follow France. Quite how the US ended up having the wrong hand free is anybody's guess.

This does beg another question though. What side does the groom stand on at a wedding in the US? Here, the bride will always be on her father's left arm as they walk down the aisle and she stands on the groom's left so in both cases the father and groom have their right arm free to use their sword to protect the bride. Is it the same in the US or has that been reversed too? (What makes you think I used to do wedding photography?)

Now back to the original question but the purge valve opening and flooding the manifold with petrol vapour does sound like a good possibility. If loosening the fuel filler cap doesn't cure it, try unplugging the electrical connection to the purge valve so it doesn't open and see if that makes a difference.

There are different programmed tunes for different years and vehicles which will also explain the different part numbers. The GEMS System document lists them, download from https://drive.google.com/file/d/1q_h1Cs5eTk550HgYUa2xz-rErBdZawjV/view?usp=share_link

Lambda sensors usually keep to the same wire colours, so if the wires on the Subaru sensor match those on the LR sensor (see at the bottom of this page https://www.lambdasensor.com/main/mcolours.htm) it will be a straight swap. You could also use that site to check that the recommended universal sensor for the Subaru is the same as the one for the P38.

Too early for digs.... I'd suspect a sticky IACV as that is what controls the fuelling at idle. If sticking closed it will give a rich mixture until it warms up and unsticks itself.