i have a 2000 civic with a JDM b16 swap.... the swap was running great for quit some time.... but now i'm having some serious problems, and thus the post.
Not always but sometimes after the motor gets warmed up, as i attempt to accelerate the engine begins to bog down. Now when this happens the speedometer jumps around all over the place too. And the whole car basically seems to rock back and forth (not violently). Also i can throw the car in neutral and try to rev the engine and it will keep doing the same thing...

i assumed it was fuel or ignition, so i replaced the distributor cap, rotor, and plugs.. checked the fuel pressure, and cleaned the fuel rail and injectors..

the only engine code i am getting is for the IACV, which i replaced, but the code did not go away even after i cleared the ecu by pulling the appropriate fuse. The weird thing about the IACV sensor light is that the car idle's perfectly. It just doesn't wanna go anywhere.

so is it the IACV sensor that is causing this problem, or what else could it be?

 

you sure its the speedometer not the tachometer..

its would make more sense so just wanted to be sure.

 

no, it is the speedometer that's going nuts, the tech is also jumping, but it's jumping with the hesitation. The speedometer just goes nuts! but that only happens when the car is driving

 

ok.. sounds like a ecu problem.

 

could this not be a timing issue maybe?

 

your speedometer is not affected what so ever by timing..
the speedometer works when the engine is not even running..

what im thinking it could be a lose ground..
that could cause multiple system to act up at the same time

 

the main hariness ground is on the thermostat.. make sure its tight.. you also have the transmission ground and the engine ground

 

well i broke down and took it to a shop.... they seem to think it's electrical... but they arn't finding anything...

 

It is probably a loose ground to the engine. I had the same problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by inline4me &raquo;</TD></TR><TR><TD CLASS="quote">It is probably a loose ground to the engine. I had the same problem.</TD></TR></TABLE>

'Tis what I would say.

Oh well, it's at the shop now, I'm sure it's something stupid & cheap .