car spuddering/tach bouncing when i have 1/2 throttle or more!!!
 

i have a mainly stock 1988 crx hf. it has the stock motor in it. when i start my car, it starts, butwhen i start driving it and the rpms are over 2500 or so, it's starts to spudder and the tach starts bouncing. it's almost as if it's dying. but it doesn't stall out or anything, and it's kinda random with the intensity. sometimes it'll only spudder a few times as it's going and then other times it's really bad. and if i keep the gas pedal floored, it'll start to backfire. now, i replaced the dist. cap and rotor, the spark plus wires, spark plugs (checked the gap and it's good), and the ignition coil. i also tried plugging the vacuum hose that goes into the fuel pressure regulator to make it have the max fuel pressure as a test on the fuel pump (1988 = old pump = worn fins = lower fuel pressure), and that made no difference at all. i also replaced the intake manifold and throttle body with another one from a del sol. all the sensors (MAP, TPS, EGR valve, etc...) worked fine and i got my car to work with it fine except it burned antifreeze like no other (intake had bigger runners and the head had smaller holes and antifreeze leaked in), and it still made no difference. so i switched everything back. the only time it went away was when i replaced the rotor. i bought a cap and rotor, but the cap was not the stock replacement and needed the msd external coil so i had to wait to put that on. but it went away for about a week and then it came back. when i put on the blaster coil and the new cap, i checked the rotor and it still looked brand new. so i don't know why it went away and then came back. today i went to start it to go to work, and it started and as soon as i gave it gas it stalled out. the ecu threw a code 15 which is the ignition starter signal. it was raining out so i'm not sure if maybe some water got in there or the humidity caused a short in the line somewhere. it hasn't thrown a code before so i really don't know if this is the problem. i'm going to have to check the wiring and make sure it's not broken anywhere or just loose. if you have any ideas on what it could be, i'm open to ideas. i have a video up on videos.yahoo.com if you search for "1988 crx hf spuddering" you can see the tach bouncing. keep in mind that it's a mianly stock hf. that means it has 62hp, at the crank, not the wheels, and the gears are ridiculously long, and it's very, very slow. i'm just trying to fix it so i can sell it to get a 90-91 crx si. so any ideas on what to check would be great. please don't reply with "junk the car" or "replace the engine" or anything that's not going to help me fix the problem.

i really appreciate you guys for reading this and any help you can provide.

oh, and if you watch the video, it's kinda loud and you can't really hear the engine. it's mainly just for the purpose of seeing the tach bouncing