1989 240sx cutting out

[frosti108]

hey. i bought my 240 with a blown engine. i pulled 89 ka24e from an automatic 240 coupe with 74k miles. i removed the emmissions ish, including egr... also removed ac. put in the pilot bearing and whole clutch assembly and 5 speed.... dropped the motor in. got it runnin... timing is pretty good maybe a bit advanced. 1st and 2nd gears both rev out to like 6k or something. right on. 3rd 4th and 5th are wacky. i forget exactly what 3rd and 4th rev out to, but 5th gear only revs out to 3500rpm and then cuts sharply down to 3k. you can hold the gas to the floor and it will slowly bog down to 3k then it picks right back up again. sometimes on the freeway i can get it up a little bit past 3.5k if im really feathering the gas. but it always ends up cutting out sooner or later. when it does i usually just clutch it so the rpms can drop under 3k and then i can resume driving. 3rd and 4th gears both cut out pretty low as well.

ive asked on all the forums and no one can really tell me whats up. i replaced the maf and nothin happened.

also it should be noted that my speedometer does not work. i changed out the gauges and still doesnt work so i think the speed sensor is bad. none of the gears show any reading on the speedo. tach works in all gears. could a bad speed sensor be cutting my gears short? could it be a vaccumm leak or something. could it be running too rich from having no EGR and cutting fuel or somethin??? is there some sort of fuel cut off maybe?

please help thanks

[frosti108]

and when i say it only revs to 3500, i mean it cuts out all together at 3500. engine loses all power. if i keep it floored, the rpms seem to drop a little slower than if not. but basically the engine just quits at 3500 and dies until you drop it to 3k then is back to normal.

[frosti108]

anyone