I have a 1989 740T, B230FT w/ LH 2.2 (No Regina/Rex). She hesitates on acceleration. Starts fine, idles fine. No smoke, no oil problems. New O2 sensor, engine and coolant temp sensors good. Knock sensor good. New fuel filter. All grounds checked. All vaccuum lines checked. Throttle body cleaned, idle adjusted and TPS set. Spark plug tips powdered whit. Suspect running lean. Warm or cold symptoms the same. Hesitates under load at high or low speeds. Gentle acceleration everything seems fine. FPR vaccuum hose removed and engine idle picks up 200 RPM, one thread said this is a test of FPR condition. Otherwise FPR return line poors fuel in a bucket with engine running. And tank return line not blocked. Help.

Couple of things:

Low fuel pressure could cause lean running - also a miss if an injector is not opening. Replacing the FPR is easy and fairly cheap.

A clogged or non-operating fuel injector could cause stumbling and hesitation. You can pull the connections one at a time to see if there is any difference in running.

Check the air intake hose to the turbo for cracks and splits which come open on boost.