Hi Paul,

Yes you have me pegged right I am a 240 man so I don’t know a lot about those two sensors except that they are trying to achieve the same outcome.

I need to ask about the TPS. Is a clicking type or a potentiometer type used on some of the last 240s. This would be the LH 3.1 system.
Those potentiometers made it on to other car makers designs like Dodge/Chrysler. The potentiometers get worn spots happening!
Chrysler had a hand in the 240’s ignition systems with less than favorable outcomes.
MAP sensors were born with Chrysler being a mid-wife to all that! Ask Caravan owners!
It does sense that manifold!

I’m not familiar with Regina other than knowing the name. It comes up a lot about a coil box having connector problems inside on other European Volvo models.
Most of the times the result made them into a FORD. Found On Road Dead. Not starting!

Those two sensors are fairly static in their readings obtained and output signal since they don’t have moving parts inside to get dirty. In others words, not like a mechanical vane or sail mass meter used on a Honda.
When they don’t start, it kicks a code, but before they die, the running mixtures cause weird performances.
You are describing a certain band of RPM miss of which is more of an “ignition drop out,” especially if it were wet at the time.
A dead spot TPS would dig on an ECU program.

If you are DARN sure your ignition system is “tip top” and then, I will stick with excessive air over fuel or lean mixtures.
This is where the O2 sensor and the ECT are very decisive in making these decisions with the O2 being on the top of the list!
I use an Electronic LED type staging meter by Actron.
It reads out in tenths of a volt increments to check my O2 sensors for laziness or drop outs.
It’s very fast and visual from a distance.
Like an oscilloscope but it’s a dedicated $40 box and its not outdated, yet!

If you have a fast (rapid sampling) digital meter set in the low range it will work too!
This way you watch for the self tuning action or adjustments in real time.
This is what today’s scam, I mean scan tools, do from the software on the newest cars for mega $ in sticker prices.
This has “ham strung” some carmakers right now!

Enjoy your 700 for being simpler in the right places.

That about all the suggesting I can do, as I’m not a 700 fan but you got most of my engine! (:-)

Phil