i was told by some people on Houston-F-Body.org to come ask you guys what could be my problem....

here goes.....my car is making me mad... when i was at a red light a few days/weeks ago, it tried to lurch forward, when it first did this i though that i just didnt have my foot on the brake well enough because i had just leaned back to tend to my screaming one year old cousin... anyhow, the second time it did it, i knew something was wrong,so i told my dad. then i drove it around as usual and at stop lights i put it into neutral (it doesnt do anything in neutral).
well, then it decided it wanted to act stupid when i was backing up too.it does the same thing in park and when i start to accelerate.
then i was letting my boyfriend chris and his friend joe look at it and joe temporarily fixed it by tightening the hose that connects the intake to the manifold. i am not getting a check engine light or anything. and i asked my friend greg, who at first thought it was the TPS, but then he told me it could be either of a few things:coil, opti, oxygen sensors, or plug wires...
i am not much a patient person and i like things to be done the first time around.. what would probably be the reason that my car is doing what it is.
thanks in advance,
-Melissa

( my friend told me it is mad at me cause i havent raced it in so long although i dont think that is the case)
oh yeah, i have a 1994 Z28, auto, with about 62,000 miles

 

is the car stock or does it have a cam in it? Because if it does have a cam it will tend to do that without a torque convertor. Other than that I would get your brakes checked out if the car runs fine.

 

my car is stock, i know it isnt the brakes, my dad and my boyfriend both checked that out...

-Melissa

 

That could be the problem... but on a more serious note.. is it doing this w/ the a/c or the defrost on? if so it could possibly be when the clutch realeases on the pump it steps the idle up a bit due to the load change and is in turn making the car move or lunge fwd.. Could this be a IAC issue?

 

When it lurches forward, do your RPM's increase at all?

 

hmmm, is your master cylinder working alright?

 

Does the RPM suddenly rise as well? If not, I give another vote for brakes. I know when mine was an auto, I had to clamp the brakes, especially when cold to keep the car from moving forward. If the brakes are fine, I would look into IAC. I doubt your coil, opti, oxygen sensors, or plug wires are causing any of this.

 

yes, the rpms go up.... it isnt the brakes because it does the same thing in park, and reverse, even if i dont have my foot on the brakes.
and my master cylinder is working.

thanks
-Melissa

 

if ur rpm goes high enough, it might be the reason.

as far as ur o2 sensor...opti...those are not the prolem...

 

what might be the reason?

 

I would look into your IAC or you might possibly have a leak on your intake manifold somewhere. Stuff like this is usually pretty hard to diagnose without a scanner.

 

ok, i guess im going to get it scanned tomorrow, i dont think many places are open on sundays...
ill tell you guys what it says.

 

personally, i think u should take it to a diagnostic machine. if it's eletrical, then it'll show up...even if u dont have an ses light, it doesnt automatically mean everything's alright.

if it's not electrical, then it's a brake problem (low brake line pressure malfunctioning master cylinder), or, your high rpm's are overpowering your brake pads, or, ya just need new pads!

 

its not the brakes, my dad and my boyfriend both went over all that stuff... ill go out there in a few minutes and look at them. i know it isnt the brakes.

like i said a second ago, im going tomorrow to get it scanned. it hasnt really been doing it much lately. maybe my car is just pmsing

 

My z is doing the same thing when I first start it sometimes. Once it warms up no problem. By the way what is a IAC?