recently the car starts jerking or bucking at around 1800RPM when its not quite warmed up all the way. when its done this i put the clutch in and let it back out and it doesnt do it. its done it once when taking off from a stop and once while driving about 10MPH, both times in first gear. it feels exactly like when you pop the clutch out at too low of an rpm. what could be causing this.....drivetrain? fuel system? electronics?
the car only has 30K on it and i havent had really any problems with it.....
anyone have ANY thoughts or ideas?????

 

hrm mine started doing that when my differential went out (last week) for a month before it went out. Mine was making noise too though when it got hot and felt like I was kinda towing something. You could check the gear oil in the tranny and the rear. check for excessive metal shavings or a burnt gear oil smell (kinda like a barbque that's been rained on).

 

im getting the same thing... sometimes before the car warms up i hear a clunking noise in the rear of the car like somethings loose but everything looks fine...

 

Sounds like you're having the 3k hesitation, but just at lower RPMs. Search the site, there are tons of threads regarding this topic. One way to get rid of it is to upgrade to a Power FC.

 

the car runs great other than the couple times its done it. it doesnt feel like the drivetrain and by upgrading the grounding wires ive almost got rid of the 3K hesitation. this feels like the 3K hesitation problem but one right after the other until i put the clutch in and let it back out.

 

How old are the plugs?

 

a few weeks old

 

I get the same thing.. but its very slight and I think its normal... My FC does it, my RX-2(Haltech E6k) does it Very slightly and the FD does it.. I think its just the nature of the rotary engine..
My freinds track FB with a P-port will do that if your trying to drive it under 3krpms.

I think its just the overlap at lower rpms.

 

I think drivetrain slop, bushings, pillowballs, rearend gear lash, U-joints, also have a lot to do with it. Mine does it

 

When cold, mine would sometimes jerk alittle and feel as if it wasn't accelerating or getting fuel. I would let off the gas and accelerate and it would fix the problem slightly. It ran ok once warmed up. I changed out the fuel filter but after I changed my plug wires It hasn't happened again.

 

lightweight flywheel will do it...my car under 1500rpms in 1st moves in surges unless i SLOWLY apply gas..over 2k its fine

 

I have these symptoms too but it applies more when I have my headlights on. It's even more bucking when my AC (...well fans, really) is set at max. It can happen too when completely cool/cold (i.e. early morning before work) but rarely has that happened since it hasn't been cold in Central Florida since last winter (lol). But once fully warmed up, car doesn't buck at all almost. It just really sucks it can happen when you're first at a red to green light...yuck...seems to other drivers around you can't drive! Haha. Fortunately, I haven't driven the car much at night for it to happen (headlights on) since I drive the car mainly during day on weekends and daily driver every other time.

Will definitely have to get this squared away soon with my upcoming tune-up - look into some grounds and such. Here are great write-ups on 3K hesitation that is similar to everyone's issues:

http://www.fd3s.net/3k_hesitation.html

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/3k-hesitation-fix-571324/

 

Mine bucked a bit, then i followed Damian's thread on how to set the TPS sensor and it went away but, it could be other things too. Start with the basics like fuel filter, plugs, air filter cleaning or replacement, ground wires with clean terminals.