Ok, so I have a 90 model crx with a z6 swap on an EF Si trans. I am having a problem while driving the car where when I am barely on the throttle cruising in any gear, I get a shudder, its like if you take off and just throw your car in fourth or fifth gear, it will shudder or jerk. It does something similar to that but it feels like the throttle is on a violent pulse until I either completely let off the accelerator or give it enough to accelerate. The car idles and runs fine otherwise, I have replaced all of the engine mounts and checked to make sure everything is tight and in its place, and it is. Replacing the mounts helped some but It's just more solid now. It almost seems as if the thing wonlt run properly under light throttle. New plugs and wires, cap, rotor, axles and motor mounts. I'm starting to get stumped and ready to give up, but It's my Rex and I love it. Any help would be greatly appreciated. I do not have any check engine lights or trouble codes or any other symptoms than what I described. Thanks in advance.

 

Maybe a new fuel filter,just a suggestion.

 

When was the last time youve done any maintainence?

Plugs
Wires
Cap
Rotor
Fuel/Air filter
O2 Sensor

 

Replaced when I got the car on the road again, been a few weeks but may try again, and I think I understated the shudder I am getting, its not like a bent or unbalanced wheel shudder, its pretty violent. Feels like the motor is just flipping in The bay. I may get a friend to ride and video it, just to illustrate. I'm kinda thinking may be tps But I have never experienced this before, even with bad tps.

 

Does your steering wheel shake? Has it been swapped?

 

Has a z6 swap, and yeah I replaced everything but fuel filter in The past two days, fuel filter was a couple weeks ago.
No shaking from steering wheel, its not wheel or tire related, this is a longitudinal shake, not lateral as a tire or wheel would cause.

 

Check tps signal, could be distrib related.. Coil, igniter, loose wire

 

just a thought check your mounts also

 

sounds like your having some sort of electrical problem. check all your ground connections, make sure the wires are clean and making good contact. could also be distributor related like previously mentioned.

 

dose it get better if the car is warm . I'd carefully spray starting fluid around your intake tube connections and throttle body and intake it will make your idle raise when your over an intake leak with the spray also i would compression test your motor and finally check your fuel pressure if you dont have the propper tools autozone rents them cheap

 

Temp doesn't affect it, dizzy is a new unit now, tps is in spec, double checked all grounds, double checked ball joints and control arm bushings and as I stated before, I have replaced all engine mounts this week.
I'm scratching my head on it now, car has had this problem the entire time I have owned it and It's almost not driveable, just extremely annoying.

 

Fuel pump?O2?

 

THink I may try a different ecu, I talked to the guy I got the car from and he said its been chipped. Think it would hurt to try my p75 on it? He said he didn't have the problem when he owned the car, but who knows. I'm starting to wonder if maybe a chip leg is bent or something.
Just a thought.

 

FIXED!
So after yet another set of plugs, another set of NGK wires, fuel system pressure check, TPS calibration and operation check and 5 different dizzy's didn't seem to point me any closer to the problem, I sourced up a virgin P28 and plugged it in. Problem solved and now I can move on to the fun stuff like driving the damn thing. Also turns out that the moron I talked to is either a liar or just stupid, because the P28 that came out of it was also virgin. I'm gonna try my original ECU in another car and see if it acts the same. I narrowed it down to quick paced surging between 1-5% throttle, irregardless of RPM, temperature, speed or engine load. It idled fine and ran fine on anything above like 10% throttle, but upon barely giving any throttle it started surging between the 1000-1100 RPM mark. Opened the computer for signs of moisture or heat damage (also to look at chip situation) and noticed nothing wrong, so I don't know. Maybe it just doesn't like my car.