Hi!

It's a 93 940 non-turbo, 136k miles, with Rex/Regina systems.

I've experienced something rather awkward: after a visit to a mechanic who changed the timing belt, the idle became unstable (sometimes stays at 750+-50, sometimes jumps between 500-1000), and about 4 months later the check engine light came on, together with slight loss of power.

The codes were for adaptive lambda trim. I cleared them 2 weeks ago and they didn't recur, although obviously the symptoms are still there.

It seems that timing marks are O.K. I'm bound to think that the belt replacement might have been a coincidence (wishful thinking, yep).

The loss of power symptoms are:

1. Intermittently, I could feel that during acceleration it would loose power almost as if I were removing my foot from the accelerator. Such drops in power would last about 1-3 seconds and recur sometimes every 5-10s, sometimes very rarely.

2. On average the power seems to be lower -- I feel that it runs in higher RPMs, and downshifts just to do about anything (even on slight inclines, like 5 degrees).

It seems that there's almost no power in 1st gear below 2000 RPM.

As a side issue, it was spewing oil from every possible seal till I got a new flame trap (old one had 3 or 4 holes open enough to have the light pass through them) and drilled the hole for the manifold vacuum from the side of the tee (it was plugged solid). I changed the vacuum hose as well, since it was dirty.

I'm planning on cleaning the oil separator just for the sake of it, cleaning the throttle body and looking for intake leaks. I'll also have a look at the idle valve and clean it at least. I'll also make a test rig to see if it responds to step impulses properly.

Anything else that I should look for? Spark plugs?

I will probably change the fuel filter, because by the rust on the fittings it seems it's the original one (don't blame me -- I've got the car only 6 months ago).

Another question: how does one diagnose the fuel pressure regulator? The diaphragm is definitely fine (removed the vacuum hose and no fuel comes out, it doesn't even smell much fuel at all). I've also tried looking for return hose flow without actually removing it (old hose, would probably need to replace it at the same time) -- when I squeeze the fuel return hose, I definitely feel the flow in it, and removing/replacing the vacuum hose to the FPR does change the flow in the return hose.

I'm slightly worried about the pressure pulsation in the return hose (while idling) -- I wonder whether other B230+Rex/Regina users could confirm/deny that on idle, when they squeeze the fuel return hose, there's a pressure pulsation of about 5-10 pulses per second. I'd rather not buy a new FPR if mine works O.K. I wish I had a fuel pressure gage -- that engine with that fuel system doesn't have any accessible valves nor fittings, I'd have to disconnect the fuel feed hose first (and buy the FP meter!).

Thanks for any suggestions,
Kuba Ober