1995 240sx: starts, runs, coughs, dies under 1k rpm

[atrombom]

My 240 starts fine, and runs well while accelerating. It was making a loud tapping/knocking noise from the top of the engine, which dissapears above idling. If you come to a stop and the revs drop > 1k it coughs or abruptly stalls. Is this an idle speed issue? It also flails the tach wildly crusing around 40mph, possibly only when it tries to shift(A/T). The check engine light is on, the guy who saw the code said it was a transmission solenoid or something worse.I just replaced the front main seal(my first DIY car repair) and today was the most i've driven it since I bought it. Any adivce is welcome.

[atrombom]

Update: replaced plugs, oil and fuel filters. Stalls a bit less, runs fine during 'warm up,' after 5-10min it feels intermittently in gear.The CEL code is "P1760 Trans Clutch Solenoid Problem" What kind of job is that to fix ($/parts/time) and is that likely my only problem?

[atrombom]

Anyone have any experience w/ this? Its so frustrating because for the first bit the car runs perfectly. It may be temperature or shifting into 4th that is setting it off.

PS: How much should I pay for a replacement transmission?

[ned4spd8874]

I have a similar issue. Will the rpm needle bounce from 0k to 1k a lot after idling / warm up?

I just brought mine to a shop the other day and they said it was the MAF. I'm going to be working on that this weekend, but you might want to look into that.