I drive a 2002 Monte Carlo 3.4L V6. I've been trying to figure this out for a few weeks now so any help would be greatly appreciated. My car has 86k miles on it. I'm having trouble accelarating. It sputters from 1000 to 3000 rpms, then once at high rpms, it feels like it grabs and takes off and the engine makes a odd sound. The best way i can discribe the sound is its like water running through pipes through your home. It does this everytime. I can floor it while going 15mph and it will sputter for a few seconds then jump to 3, 4k rpms and drive fine except for that noise. I did the basics and replaced spark plugs and wires. The noise led me to believe it was an exhaust problem and after some local autozone advice I replaced EGR valve. It didnt make a difference. I tapped on the catalytic converter and it didnt rattle so i figure thats not clogged. I've read replace the fuel pump alot however why does it work fine at 3000rpms+? There is no check engine light on. I'm not sure if a failing fuel pump or clogged exhaust would prompt it to come on. If anyone can help me, id really appreciate it. I gave pretty much all the info I can think of, but if anyone has questions, id be happy to answer them. thanks.

 

Sounds like it is pinging. The car may be too lean. Check the fuel pressure.

 

Get the codes checked on it.

 

recently, ive gotten multiple codes from my monte. i got a cylinder 4 misfire, system too lean, egr fault, and now i have a multiple cylinder misfire code that has stayed on. the car is making more and more odd noises when accelarating which leads me to believe it is a vacuum leak. any ideas?

 

Recently had a similar problem to this on a 2001 Monte Carlo. Car ran bad at idle and low rpm's, but ran fine at higher speeds. Replaced the fuel presure relay that is located on the fuel presure line that conects to the fuel injectors. Made a huge difference. Also be aware that it could also just be a vacuum line that conects to this. Found this off once. Car would start poorly and also stall and die at a stop. Hope this helps and helps anyone in the futur. Also a note on the codes, no codes, not evan a check engine light on when this was happening.

 

Mass Air Flow sensor on the intake may be filthy, check it out.
TPS sensor may be out of range