1990 honda crx jerking when I get on it?

CHANGE the FUEL FILTER and also clean the THROTTLE BODY and the IDLE AIR CONTROL VALVE! Get a can of AMSOIL POWER FOAM and clean them to SHOWRROM CLEAN! Running the AMSOIL through the PCV will remove YEARS of baked in SLDUGE on the PISTON RINGS, and then use ONLY PENNZOIL ULTRA PLATINUM OIL that is made from NATURAL GAS and NOT crude oil! You will TELL the difference at ONCE! Use ONLY DENSO Twin TIP IRIDIUM LASER PLUGS ($7 each) from ADVANCE AUTO! They bring out the BEST in POWER and ECONOMY and LOWER emissions as well! CHANGE the AIR FILTER! Get the VALVES adjusted If you were in MICHIGAN I would do this FOR YOU! I CANNOT tune ANY engine without AMSOIL POWER FOAM! try to find a CAN of it ONLINE if you have to! CLEAN BOTH SIDES of the THROTTLE BODY PLATE! >>>BTW>> there is NO SUCH THING as a "GAS" pedal anymore??Only an "AIR" pedal! Your FOOT only opens the THROTTLE BODY doorway to allow AIR into the engine and the GAS follows suit from SENSORS and a CLEAN IDLE AIR CONTROL VALVE and T body and clean PCV system! >>If you do ALL this cleaning up and STIL have an issue, get a can of LIQUI MOLY CERA TEC and it will FIX holes in the CYLINDER WALLS! It is TUV rated! Only the BEST things in EUROPE get a GREAT TUV rating! You MAY even have a BAD FUEL PRESSURE REGULATOR as well! There is NO CODE FOR THIS and it must be CHECKED BY HAND! It is on the FUEL RAIL and if the VACUUM is removed an GAS spurts out, the unit is BAD and must be replAced! DESNO TT IRIDIUM PLUGS bringthe BEST out of ANY CAR or ANY ENGIEN there is out there! TRY and SEE! GOODLUCK and MERRY CHRISTMAS! Send me a X mas card and a box of CANDY! LOL! REALLY MUSKE 1t 31800 VAN DYKE AVE; WARREN, michgan; 48093 I  ALSO accept GIFT CARDS MY ADVICE is GOLDEN once you get this thing DONE you will have GREAT RIDE for another 50,000 miles! BE SURE that your TIMING BELT is OKAY FIRST as these engien are INTERFERENCE FIT an a broken TIMING BELT will BEND VALVES>>PRICEY repair!>>ALSO if your SPARK DISTRIBUTOR is mounted on the SIDE of the CYLINDER HEAD and driven by the CAMSHAFT< remove the DIST CAP and wash the INSIDE OUT with BRAKE CLEAN or ELCTRIC part cleaner! OIL will SEEP into the HALL EFFECT and the car will feel FUNNY as the SPARK gets confused where to HIT ON!  NEVER USE Valvoline oil either! NO FACTORY on EARTH will use it! IU have fixed DOZENS and DOZENS of HONDA engines and tuned them to PERFECTION! 

get something made in this century

Cracked intake bellows....

Change the spark plugs and adjust the valves. 

It is possible your fuel filter is a bit dirty and is restricting fuel flow at higher demands.