several things replaced:
KS, valve cover gaskets, intake gaskets, spark plugs, coolant
plus mods:
headers, Y pipe

After I picked the car from the shop, I noticed 2 weird things:
1: the car starts really hard (approx 2 seconds of cranking compared to a turn of the key before)
2: every time I press the gas pedal, the engine hesitates for ~ half a second; that translates in 2 things:
a) when I release the clutch, the engine seems powerless for a moment
b) while driving, if I release the gas, wait a few seconds and then press it again, the engine seems struggling at first, then it accelerates as usual

Except these problems, everything works fine, the car pulls strong.

One last thing: the car is Cali spec meaning that after the Y pipe installation, 2 oxygen sensors (post cat) are out in the atmosphere - this shouldn't influence the way the engine works - I think ...

Any suggestions?

I'll probably have to go back to the shop Tuesday but I hope one of these things:
1: easy fix - solve the problem by then
2: finding out what it might be and knowing what to tell the mechanic

Thanks in advance!

P.S. No CEL, smooth idle, no other problems

 

try and pull some codes

 

I think they cleared any code after replacing the KS; I'll drive it a lot this WE, then I'll go to Autozone.

 

are you sure they hooked up the sensor? almost sounds like the KS is not hooked up. just wondering ... what did they charge you to do the headers? I bet it wasn't cheap ...

 

yeah i would pull codes again. ks doesnt throw a cel and i do agree with jtz it does seem like knock sensor related problems

 

I gotta say I think havng 2 o2 sensors connected but swingin in the breeze will affect responsiveness. The engine is still collecting data from them and the data is dead wrong so I don't see how everybody thinks this has nothin to do with the problem. But Mabye you guys know something I don't. I would think having the sensors disconected would give the ecu better info to go on.

 

Strange stuff:
I went this morning to check the KS ... I couldn't see it !!! I said WFT? and I started pulling everything apart to make sure if it's there. After half an hour I finally saw it and realized that the cable was rerouted lower - that's why I couldn't see it. I put everything back, I started the car ... Everything was fine, it started right away; I stopped the car, I started it again - started fine; I left it running until the fans started blowing, I stopped it, I started again - perfect; I drove it for a while in the parking lot - everything is back to normal. Really strange but I'm happy!

To answer another question, only the after cat sensors are out; they are there to asses how the precats work. So they shouldn't influence the the engine works; the precats sensors are fine (they help regulating the fuel/air mixture). Sometime in the future I'll try to build simulators for those sensors ...

Thanks for all the help and suggestions!

 

i bet your glad you didnt bring it back to the mechanic god only knows how bad he would of screwed you for his own mistake.

sorry if you get along with him i just dont trust alot of mechanics.

 

he's a really nice guy, he promised me he'll do the job in one day, it took him 4 (I brought him bad parts - my fault) and for the 3 nights the car was in the shop, he gave me a car to drive around and the price was as agreed at the beginning.
I'll probably end up going back to him because the exhaust touches the frame some times and it's annoying