rpms drop while in gear

[reyna]

IM having this problem on my 2002 Monte LS for a while now. It has 65K miles.

Whenever I fisrt you the car in the morning everything feels fine. Shifts good and idles fine. But after like 30 min or sometimes when I take it to work and start it up to go home it has idle problems and shifting problems.

It starts then when im in gear the rpms will drop slightly like 100 rpms. When im in a stop the rpm will constantly drop 100. If I put it in park or neutral it will idle fine. Every time the rpms drop it jerks and is very noticable.

On the highway is another problem. When im doing 50 and the car is in OD the rpms will be about 1500. When I give it a little more gas the car will jerk like its not getting fuel for a split sec. It would do this untill I reach 60 or rpms reach 2000.

Is there something wrong with my trans or its it something else. It only does this once im in gear.

[sharkey]

i run into the shudder/miss feel in od at cruising speeds all the time. what it usualy tends to be is ignition problems. at cruising speeds, your car is in lockup (the torque converter clutch is fully locked) and this will put more of a load on the engine. when you put your foot into it slightly, it loads the motor harder and any fuel/ignition issues you dont notice anywere else will become very apparent.

id recomend checking/changing plugs, wires, fuel filter, check your fuel pressure. those seem to be the common things that can cause this issue.

[bszopi]

I'd lean toward coil packs.

[SHOoff]

On the highway is another problem. When im doing 50 and the car is in OD the rpms will be about 1500. When I give it a little more gas the car will jerk like its not getting fuel for a split sec. It would do this untill I reach 60 or rpms reach 2000.

When you hit the gas from that speed it the RPM should jump up right away. Usually goes over 2000rpm, would be at least 1800, even though you're at the same speed. Does it do this? How does the car act when you go to WOT?

[reyna]

The maintained very well. I change everything that needs to be changed at its time. The plugs have recently been changed also but ill check into it again. I'll also check the coil packs.

The only minor mods are an open air filter, u-bend delete and a pulley from FFP.

[reyna]

When im doing 50 my rpms get to 1500 sometimes even lower and thats when I have even less power. If I press on it slighly it wont shift down and it tries to get to speed normally. If I press on it harder about about 25%of the pedal it will shift down fine and go. Under WOT the car runs fine. NO hesitation. In the city the car also runs fine. Its only when its on idle in gear and when the rpms are too low and you press on it slightly to go faster without it shifting down.

The car shifting is very noticable becasue I have dual flowmasters. When the rpms are low its a very low rumble.

[SHOoff]

U-bend delete? Is this on a 3800?

Since it's not giving you any trouble at WOT (i'd sure bet that an ignition problem would let you know then) and it's only at idle. And it's not holding idle very well. I'm guessing maybe it's a vacume leak.

Thinking maybe one of the gaskets for the intake manifolds.

[reyna]

The LS also has the ubend. How do I check for a vacume leak or gaskets.

[SHOoff]

One thing that you'll really like to know is that the GM 60 degree V6 (well, the newer ones anyways) are really popular for blown intake gaskets. I havent had it happen yet, but I believe that if the lower intake gasket is blown, it will leak coolant most likely by the sides of the head . Near the LIM/Block area. I'm sure someone here knows MUCH better than I do on that one though. For the upper intake gasket I doubt has much of a sign like that, since it just keeps the upper and lower sealed, and keeps air from leaking.

[eliteweapons]

Might want to check the iac as well.