ok...to start things off i bought a 97 z28 a4 completely stock....ihave a hesitation to where if you step on the gas it takes like that sec for something to read that you stepped on the pedal now what kinda thing...idle is fine....doesnt surge or drop rpms...i put new plugs in and the wires look good, i cleaned the iac, air,fuel are new...now what?? im thinking coil and module next....i work for acdelco so i get parts at cost.. i havent changed o2's ither...but thats lke almost 150$ right there and i would liketo make this stop with only like 40$...the car has only 66,000 miles on it .....stock everything...

if your rolling at like 5mph or 10 and you stomp on the gas the car lights up the tires...and i cant figure this out? it bothers me cuz i dont wanna try t race someone going like this? i hink the car should have a lot more power! help me thanx

 

How about the fuel filter. A slightly clogged or old filter can cause a slight hesitation, especially under load or WOT.

 

all that is new! i cant understand why this is happening...im stumped any and all replys would be greatly appreciated!

 

could the opti be going out maybe? what about your air filter, maybe it could be pretty dirty... not sure but good luck man

-Mike

 

i dont think it could be the opti cuz of the fact that the idle is good....doesnt fluctuate or drop or rise...im planing on doing an opti change this winter when i store it...dont feel like doing it on my days off when i could be driving it!

the only other thing is...would o2 sensors make your car hesitate even though theres no code being thrown??

 

not sure on the 02's, i have two codes thrown on my now as we speak and they are both 02's.. so im not sure

 

yeah i changed plugs...and i made sure wires were good not burnt...also at night made sure there was no arking...shoebox said swap coil and module...so i might do that!

 

I'm just guessing here, but would the TPS have anything to do with this?

 

I was also going to suggest the TPS. If the car doesn't actually run bad, just has a hesistation before it kicks in after hitting the pedal, it could be your throttle position sensor. Or, maybe even some slack in the throttle cable.

 

From my experience so far:

If it takes longer than one crank to start: coil or coil wire
slight hesitation like you're talking about: opti

I recently replaced the opti because I was tearing into the engine anyways and it had 100K+ on it and it solved the hesitation. The engine pulls much stronger and the difference is especially big at low rpm's (up to 2500). I know everybody says a bad opti will only manifest itself at high rpms but my experience is the above.

The other thing that could cause this is bad O2's and you can check those if you can log some data. Do you have a laptop and an ALDL cable?

Sam

 

I guess I should specify that I did check the O2's, TPS, air leaks, etc... and I knew those were all good before I replaced the opti.

Sam

 

sweet guys...thanx!

but when you say there might be slack in the cable? do how would i go and tighten that? and if i tighten it wont it raise the idle and rpms?? how would i go about doing it...

maybe if im bored ill do the opti! i doubt its that though