Hey guys, I've been looking all over for answers but cannot find anything. I have a 93 vx completely bone stock, since I bought it it has had a weird pulsation under light acceleration/low rpm... when I say pulsation, imagine throttling the gas pedal on/off/on/off... I noticed it really only does it when hot (the hotter the worse), does NOT do it when the cel is on... no cel codes stored... while pulsation happens the speedo also dips at the same time... I have tried different clusters with no change, tried multiple and brand new vss... cleaned iacv, egr port, checked for intake leaks, cleaned injectors, checked mechanical and ignition timing, replaced spark plugs... any ideas would be great..

 

Can you explain what you mean by "it does NOT do it when the cel is on" ? Cause you said there are no stored codes. If the check engine light lights up then, without turning the car off, pull all the codes. It sounds like it's a code that is erasing when you turn the car off.

 

What I'm saying is that if I turn on the cel (say by unplugging the vss) then the symptom goes away. So when I make the cel come on the symptom goes away

 

My friend had a vx and I guess it is a widely known issue. I can't remember what it was though. He called it, "the vx stumble."

 

The VX stumble is the transition between lean burn and non lean burn. The VX uses a special 5 wire O2 sensor and unless you get the correct (read expensive) one it will continue to do this. When I first bought mine, I mistook it for VTEC kicking in, which is 2500 rpm on the VX. There's a lag in throttle response and then WHAM, it takes off like a, well, like a faster VX.