Here's a stumper... 4th gear/3rd gear power loss

[Dan Vincent]

Last week I went home to the beautiful Berkshires here in Massachusetts for spring break. All the snow aside (grr), there's lots of hills and other stuff to climb. One thing I noticed is that at some point in my bird (97 3800 w/Y87, auto), I got some serious power loss at around 1800 RPM going up certain hills. Maybe I was being too light on the gas, but the revs would go up to 2000+, maybe around 2200, and then drop down to 1800 while the car made this... not a squeal, but kind of low, rotating grumble. Pressing down on the gas a little more makes it downshift, which is great, but then I accelerate too fast, and then I let go, car upshifts, back to 1500 RPM, and then touch the gas again to hear the noise.

This only happened on very specific hills (in fact, it didn't happen at all on the one near my house). I also never have this power loss where I normally live, and on the highways I can easily go up to 2.5K RPM when I'm cruising along at 75 MPH.

Any clues? There's no SES lights coming on, so I'm guessing this isn't a critical thing - it's just an annoyance. One guess is a failing torque converter, but I'm not too sure. Anyone have an experience like this before? Thanks for any replies in advance.

[ March 22, 2004, 11:28 AM: Message edited by: Dan Vincent ]

[Jason McCallister]

Put it in 3rd and set the cruise control. See what it does then....

[Turbo V6 Camaro]

sound like tranny sliping?

[Ex-5.0]

Could be misfire under high load, low RPM condition like you would have climbing hills in 3rd or 4th gear with the torque converter locked. I'd look at plug-wires, plugs, coil packs first.

[Dan Vincent]

Yeah, but I just had that stuff replaced a few months ago (plugs, wires, coils). If it was a misfire, would not the SES light blink (as it did to me in the past)?

I've got a service manual, so I might take some time to look at stuff, but the weather hasn't been cooperating around these parts.

Thanks for the ideas.

[FloydSummerOf68]

Whenever going uphill I'd just keep it in 3rd and not D so that it wont shift around as much...

[Dan Vincent]

A slight update...

Driving to Springfield today (to visit Pep Boys, natch), I had the problem - around 40-45 MPH, pressing the throttle didn't do much. Later on, even when I pressed the throttle down to get more power to accelerate, the revs went up normally but then dropped down immediately to around 1500 - even as I held the throttle in further I just couldn't get any power. It even did this on flat roads, and not just hills.

The funny part is that on my way home, on the exact same roads, it behaved properly! Maintaining speed wasn't an issue at all; letting go and pressing the throttle resulted in proper behavior.

The only other time I've experienced something like this was when a car ran out of gas on me. Could this possibly be a starvation issue - fuel filter (I had over half a tank of gas)? The inconsistency of the problem is what's gnawing at me, and is hard to describe in a textual form. Maybe it's time to get a pro to look at it.

[ March 29, 2004, 11:11 PM: Message edited by: Dan Vincent ]

[Chrisz24]

mine does the same not to worry

It is right around the 45-50mph if your light on the gas, the car is shifting from 3rd to 4th and the RPM's really drop.
It's just your trans hunting for the right gear, the good thing to do is shift to 3rd, but I notice the same thing- feels like a manual in a gear too high, and if you gas it down enough to downshift it takes off and keeps accelerating.

Shifting to 3rd is good sometimes, keeps the trans temp down, and keeps you at a steady controlable speed.

Hope this helps some

[Dan Vincent]

I should have added that I did downshift to third when I had the loss, and it didn't make any difference, apparently.

[Turbo V6 Camaro]

check your TSP and MAF

[LD]

my Grand Am acted similar when I had a bad fuel filter/pump