97 Honda Prelude, when using the A/C the car overheats when in stop and go traffic or stopped. If I go 50 mph or more the car is fine with the A/C on. What part do you think needs to be replaced

Verify fan operation(be carefull not to let the car overheat) and if they dont work try these steps. (If you have electeical know how)
check all fuses
check relays by swapping with another known good relay.
look around with a tester and see where along the circuit you are getting voltage.
replace the
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Low pressure when at idle, after the engine has warmed up and the oil has thinned, indicates that the oil pump is worn and needs to be replaced.

Could be blown head gasket, if so you should have quiet a bit of white smoke also if this is problem.

will try to help. the fan you replaced, was it the air conditioner fan? if so. then you need to check your primary fan. the one that does come on when the engine reaches operating temperature. make sure by starting engine, let the motor run and the temperature guage reaches the normal operating temperature.if the main engine cooling fan does'nt come on, then you'll need to check the fuse box under the hood. relays are black square plug in's they are marked and will[fan relays] tick when you turn the key on] if main engine fan does not come on when engine overheats, #1 fuse blown #2 relay bad #3 main cooling engine fan bad. note; the air conditioning fan will come on with engine running,when air conditioniing is turned on. when the a/c is turned off, the a/c fan will not be turning. hope this helps and as always, thank you for choosing fixya.com

sounds like your clutch is not engaging all the way

Sounds like a crank postion sensor. Is this only when the car is hot/reached operating temperature

not enough fuel the map sensor needs remapping

Check the fuse and relay for the cooling fan before it overheats again so you don't blow the head gasket on the motor. After you replace the fuse/relay let it idle keeping an eye on the temperature gauge, make sure as it reaches a little over half way the cooling fan should come on. If it does'nt then your coolant temp sensor may be at fault. Good luck and be safe.

the trans will actually bolt up to the engine..but it will not work properly without the pressure switch plugged in to the harness... if u notice, there is a hole with no threads in the prelude trans..u couldnt even thread a 3rd gear pressure switch in the trans case..trust me ive seen it b4 at the dealer where i work.. i even went as far as installing the trans and when going back together, saw the difference when trying to plug the harness in...its not the same..i laugh about it now, but was very mad at myself at the time for assumeing the parts guy brought me the right part..the guy with the prelude was about to install my accord  trans in his prelude ...luckily i was able to stop him b4 he installed my trans in his prelude...i laugh about it now

Which tranny solenoid are u reffering to? What is the actual problem u r having?