my tach has been going nutz ever since sunday coming back from fontana....it jumps up to like 7k and never seems to match the real rpms and the shift light keeps going off. during this my engine is acting really weird. The engine will pull then power will drop like 50% then pull then drop 50% and so on wtf?

 

Sounds like your ignitor is going out. Replace it.

 

but the rpms on the v-afc arent going crazy

 

I had the same problem. Check your wire connection from the vss the the drivers shock tower.

 

vss? what does that stand for?

 

vss just figured it out vehicle speed sensor
my car actually threw a code for this a long time ago but it never did it again and never had this problem
where exactly is this vss on a 99coupe

 

Also make sure your Battery's negative terminal is grounded good. The same thing happened to me and that is what is was...Matt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ekhybrd &raquo;</TD></TR><TR><TD CLASS="quote">vss just figured it out vehicle speed sensor
my car actually threw a code for this a long time ago but it never did it again and never had this problem
where exactly is this vss on a 99coupe </TD></TR></TABLE>

Its on top of the transmission. Right above where the axle goes in the trans (passenger side). My plug was all corroded up. Unplug and plug it in a couple of times (is has 3 wires). That might rub enough corrosion off.

 

i checked all the grounds and made shure the ground on the battery was good. The problem has went away....if it comes back i will check the vss