My girlfriend bought a 2000 monte carlo ss NA3.8L from a dealer used lot back in December.

recently it has been hesitating on startup, sometimes stalling. When I got in it to drive today it sorta started funny, then put it in drive and pressed gas pedal and i was barley getting it to move abouve 10mph. Floored it and it wouldn't get going like it was struggling to breath or starving for fuel. It was moving but like it kept falling flat.

Originally when she told me about this, I also noticed it would shift hard every now and then and could hear slight whine noise as if power steering fluid was low. I also noticed the "rotten egg" smell from her exaughst. Figured it was all due to Cat being bad and changed it and the downstream O2 sensor. Filled power steering fluid as well and changed fuel filter while I was under it.

Unfourtunlatly like I said even after changing these, it kept hesitating when I tried to leave driveway even while pedal was floored. The tranny was still somewhat shifting hard with the noise but it comes and goes. Im assuming from what I read, this is due to a bad sylinoid thats known to go bad?

Only other this i can think of that would make the motor fall flat like that is the fuel pump, but I am going to dig my gauge out tonight and test fuel pressure. I think its supposed to be 56 psi?
Possibly Mass Air sensor or MAP sensor?
Fuel Pressure Regulator was serviced for recall in '04

Sorry so long

 

ok so I should mention there is NO check engine light. there never was..........
I checked the fuel pressure tonight and it was roughly 53 psi on initial prime and when engine is running it is 45psi.

After the initial hesitation goes away, the car seems to run fine. Kind of at a loss now that Psi seems about right. any suggestions? I just think its odd that no codes are setting off the check engine light but obviously its something going wrong.


just a side note, if you ever have a odd clunking noise almost like a "tin knocking" sound and its not your heat shield for the exhaust, check your Emergency brake. I pulled the rear rotor off to find the emergency brake horse shoe flopping around loose inside the rotor. Bent the retaining clip back and realigned it into its proper location and all was good

 

anyone?

 

I am no expert...but you could probably check the MAF sensor. I've heard those can cause it to stall/hesitate.

 

did you ever do a tune up on the car? could be something stuped like the PCV valve is clogged up. i would also clean the MAF sensor. mabe it needs plugs, but by the sounds of it not likely. my car does a similar thing, and i've tried pretty much all i can think of. it still has a dead spot in the throttle ( though not as noticable scince i hollowed the cat out) and scince it has almost 160k miles on the odometer i suspect the trans is starting to go.... how many miles are on your car?

 

its got 110K. I know it still has stock ignition wires on it so I am going to run through them and see if any are starting to go. I will end up changing them all and the plugs soon anyway. I may pull the fuel pump out just to check the screen in it, but I doubt thats what it is. Few bottles of injector cleaner as well........ See what happens.

I had a lumina that did something similar to this, but it would take off normal but stumbled at full throttle.... Due to bad MAF sensor. a bottle of the spray cleaner may not be bad idea either.


Have you checked the spark from each plug wire? alot of times the coils will go bad, and on 2 different cars now the back plate that the coils bolt to has gone bad as well and will cause loss of power

 

I think starting with the MAF cleaning is a good start and it is pretty cheap! I am wondering about your cat, I've heard they can be pretty troublesome on these cars and are known to go bad. Hell, mine went out.

 

my monte had the same symptomes as you describe. Finally the car just started to grind instead of whine. The tranny had to be rebuild and also a planet gearset had to be replaced.
My recommendation is take it to a shop that can work on transmissons or take it back to the dealership as soon as you can. This is the second trans i go through in the last 3 yrs.
Good luck, hope i didn't scare you.

 

I would start at the MAF, clean that...

Other thing would be plug wires/ ignition coil pack...

 

Sounds very much like a MAF problem try tapping it lightly when the hesitation occurs. Or unplug it and see how it starts. Change the fuel filter too if it's been awhile. And the PCV could be faulty which would cause poor manifold vacuum and bad fuel pressure regulation.