Unusual power losses with acceleration.

[Gatt9]

Hi all, I'm having some unusual power losses with my car(See bottom for specs). It occurs at two points.

1. First thing in the morning, only when it is cold(Say < 50 degrees faranheit), if I run my car before the engine temp gauge is registering a change my first and second gears will wind out very loudly without producing significant acceleration. It'll maintain a given speed(No specific speed), but it won't accelerate just loudly proceed through the gears. Once the engine is warm, it works normally without issue.

2. When I punch the gas, like on the highway, I'll get some acceleration but nowhere near the rate I get if I only give it a small amount of gas. A small amount of gas generates significant acceleration, but a large amount just makes more noise and produces the same or less.

Any ideas? This has been ongoing for some time, doesn't throw any error codes.

1998 Firebird 3.8l v6
95k miles
(Just did these in the last 2 weeks)
Whisper Air Lid
NGK Iridium Plugs
Taylor Spiro Pro 8mm wires

Also did oil pan gasket and used a can of "proffessional" fuel injector cleaner too.

[GinsuGuy585]

Re: Unusual power losses with acceleration.

Sounds like it's running too rich/lean. Reset the ecu and it might correct the problem.

If you have an obd2 reader get some info on what the sensors are reading.

[josh98bird]

Re: Unusual power losses with acceleration.

so when you floor it doe you hear the engine rev up but no accel or does the engine not rev up??? If the engine is revving and such but no go then your tranny is going out.

[Gatt9]

Re: Unusual power losses with acceleration.

so when you floor it doe you hear the engine rev up but no accel or does the engine not rev up??? If the engine is revving and such but no go then your tranny is going out.

Both times I'll hear the engine rev. In case 1, it'll wind out the gear but won't really switch gears, though I've never thought to push it to see if it'd redline on the RPM gauge(Which does register the increase, but i don't get any acceleration). It's not a case of not going anywhere, like if I'm going up a hill at 20mph I'll continue to go up the hill at 20mph but I just won't accelerate and the engine will roar. Which now that I think about it, it does kinda sound like it should be switching gears and isn't switching doesn't it?

In case 2, it'll rev and shift normally but I won't get the increase in acceleration I'd expect from putting the pedal to the floor. I get more acceleration from pushing the pedal down slightly than I do from flooring it.

Once the car warms up and I've got a temp, or when it's warm out, Case 1 doesn't happen. Case 2 is something I've just taken note of fairly recently, but thinking about it I believe it's been doing it for awhile.

Does that sound like a tranny issue? I've gotta get it inspected shortly, so I can get the shop to check the OBD codes and reset the ECU. Could I actually be looking at two seperate problems that just seem similiar?

Edit:

Thank you both for your thoughts! Much appriciated!

[zymose]

Re: Unusual power losses with acceleration.

It sounds like a tranny issue to me as well. I would get the fluid and filter changed in that sucker pronto. BE SURE TO CHANGE THE FILTER! I have encountered 2 tranny replacements in the last year because friends took their truck to a "quick lube" shop and they changed the fluid, but not the filter. Both of them ended up getting the filter clogged and cooked their transmission. Of course

At first it wouldn't want to kick into overdrive. Then it would quit shifting into the high gears at high RPMs. Finally, if your lucky, it would only have first gear.

Usually the transmission slips more when it gets warm, rather than being cold like yours, but I still wouldn't chance it. I would change that fluid and filter asap, and maybe even think about adding some anti-slip additive. Not a big fan of the stuff, but I did use it in my old Grand Prix when it started to go out and I got another 40,000 miles out of it before I sold it.

[GinsuGuy585]

Re: Unusual power losses with acceleration.

No experience with auto trannys, but the bogging down is based on throttle position not rpm; doesn't sound like a tranny problem to me. Did you try resetting the ecu? If you don't have an obd2 reader you can unhook the battery for an hour or two.

[Gatt9]

Re: Unusual power losses with acceleration.

I wanted to follow up on this thread for two reasons.

First, and most importantly, I want to thank the responders! The problem was the transmission, The OBD reader came back good, so I had a flush and filter done.

Second, I wanted to describe the results so that if someone goes searching down the read with a similiar problem they'll have more to go on. The problem has cleared up, shifting from 1st to 2nd is hard, but I have no issues with it winding out the gear or power loss on gear shifts anymore. I'm assuming from the way 1st to 2nd shifts I'll end up doing a tranny at some point, but atm I'm fine.

Apologies for bumping an old thread, just wanted to get those two things out there.

[vanbibber]

Re: Unusual power losses with acceleration.

no appology needed. thanks for updating it for future users :tup: it'd be nice if people did that more often