I have a 93 2.3 prelude with 107K miles. It has been surging like crazy around 2000-3000 rpms and also stalling at idle if the revs aren't held. Now the tach, bounces all over the place with no effect on the engine except the occasional surge. It will even go down to 0 rpms while I'm driving followed by some surging. I have tried running it with the throttle position sensor unplugged but it still does the same sh*t.

Any input would be cool. Thanks

 

Check all your grounds. Then go from there... timing, plug wires, rotor, plugs, vacuum hoses... etc. Are you getting a check engine light?

 

no check engine light, but plugs, wires, coil, dizzy, fuel filter, cap and rotor, are all pretty new.

Also today, it ran fine for some reason, but then at night it went back to crap.

I do get a code 12(egr) when I drive a while on the freeway, but its not related, I don't think, cuz I even tried disabling it but problems were still there.

I was maybe thinking that the ecu was messed up.

 

nah with an egr code and ur bouncing idle uve more than likely got vacume issues, check all the hoses around the mapp sensor and that the vacume hose to the egr valve is on there correctly, check for any leaks cracked or damaged lines, also check all the hoses coming off of ur intake manifold, if ur plugs/wires/cap and rotor/ dizzy are all fine u shouldn't have these issues, u can also try using a cleaning solution on ur eavc valve see if that clears up the problem and if it gets down to it decarbonize the engine.

 

With a vac leak, wouldn't the engine move with bouncing tach needle. I have ran seafoam carbon cleaner through the valves and cylinders, but what is the EAVC or did you mean IACV (idle air control valve).

Also, I forgot to mention that the motor likes to back fire at idle, and after a hard rev.

 

I have had no problems for about a week now, but I have done nothing to repair it, so I was wondering if anyone had any guesses about what happened so it doesn't happen again.

 

Maybe it was because Mars was so close.