99 Cavalier surges (reverse surges)

[mattvernon]

Hi all,

I have a 1999 Cavalier Z24 - so 2.4 liter. Manual transmission. It has 130,000 miles. Here is what she is doing:

When i drive in town at various speeds she runs ok. When i get an open stretch of road where I can maintain a speed of 45+ for more than 2-3 seconds The car starts to sag. What I mean is that you feel the car settling back like the motor loses power. There is no difference in engine noise, and I hear no knocking or anything. The RPM gague will drop a tiny bit but not much at all. This also happens with the cruise control on or off.

Here are the steps I have taken so far:

Replaced Fuel filter
replaced spark plugs
replaced tps
replaced fuel pump
replaced MAP sensor

Each thing made no difference what so ever. Please help if you can, I am ready to drive it off a cliff!

Matt V