NEED HELP ASAP < TONIGHT!!!!!!!
 

QUICK HELP!!!! i am looking into buying an SE .. the body is straight,,, the engine runs smooth... two major problems... surgig rpms at idle.... and when you accelerate after a shift the rear end makes noise. ( driveline? differential? ) so first off what makes it surge? and shoudl i be looing ito the driveline or the rear end? PLEASE HELP FAST...... might be gtting this car tonight

Is it after every shift (the noise)? If you're just cruising, get on the gas, then off, then on again in rapid succession and see if the noise persists. If so it's likely a broken mount or fouled gear set/shaft/shafts.

basically it does it whenever you accelerate..... i was thinking mount or u-joint, but i have no idea how these rear ends work...... havent worked on an RX in over 8 years and it was a first gen.. oh and it does it in all gears so i am assuming not trani....... any suggestions on the surging idle?

I dont see how the gearset is to blame. If it shifts fine and doesnt grind gears. Its more likely a diff bushing. The surging could be caused by a number of things, but first i would put a vacuum gauge on it and make sure it doesnt have any leaks.

The surging idle can be any number of things from an intermittent current drain to an out-of-spec apex seal. It's hard to say, likely it's the TPS or some similar minor ailment.

If it does it under accelleration in all gears then it is likely a broken hard-part. Your shaft is failing or your rear is loose/has a broken mount...or something else along those lines. Not enough to deter me if the deal is good.

If a tooth or gear is damaged in the rear end it could cause an intermittent or "certain circumstance" noise...unlikely but possible. The rear end has gears, too.

well he is asking 700.00 for a base model with stripped interior,, current registration, new clutch, new tires,,, but i need a car i ca drive ot work everyday.... oh and did i mention that the voltage was registering at 14 v when i first got in... and about 11 when driving?

Oh really? Ill be damned.

i would say mor e of a bucking feeling.... that jolts the back of the car

700 sounds like a very good deal to me. See if he'll let you do a compression check. Either way, I'd still get it. On the other hand, it might not be the best daily driver, especially if you don't have another car. RX-7's are never a good choice if its your only mode of transportation. If you have another car you can drive if this one breaks (or while you fix the diff mount or whatever) then go for it.
Also, it sound to me like a broken diff mount, possibly a bushing. Either way, I bet its diff related.

well where would i get a diff mount? probably not your locla autparts store? any suggestions on the surging guys/gals? i am thinking electricla sinc e the voltge drop