Car loses acceleration but not power while driving

While driving my 1998 Chevy Prizm, my car lost the ability to accelerate but the car never lost power. I managed to pull over and let the car run for a bit before trying to accelerate again…the car only got up to 30 mph and wouldn’t go any faster…after a couple of hours the car run okay. Can somebody please tell me what could be going on? I got new spark plugs, oil change, and an idle air control valve

I’m not totally sure if I understand “lost ability to accelerate, but never lost power”, but here are some thoughts that come to mind:

The fuel filter might be partially clogged. When was the last time that it was changed?

Or, it is possible the catalytic converter is clogged. A mechanic can check this with a vacuum gauge.

You didn’t tell us whether the car has an automatic transmission or a manual trans, but if it is automatic, this could be indicative of a trans problem.
When you are unable to accelerate past 30 mph, is the engine revving at high RPMs, even though the car’s speed doesn’t match the engine speed? (Hmmm…Is that what “lost acceleration, but not power” means??)

If this is the case, the first step is to check the level, color, and odor of the trans fluid.
Please do that and then report back to us on your findings. The fluid should be up to the full mark, should be a pinkish-red color, and should not have a burnt odor.

If this car has a manual trans, this problem could even be the result of a slipping clutch.

Please post back with answers to the questions that I have posed.

Sounds like a clogged cat, but we need more info.

“Lost ability to accelerate, but never lost power.”

I’m still trying to wrap my head around that comment. It has to be a slipping transmission if I’m understanding this correctly.

My guess is that the OP is saying the engine still seems to be revving fine, but the vehicle isn’t going as fast at it should be.

If I guessed what the OP is saying correctly…then this clearly sounds like a transmission problem.

Automatic or manual?

My car is automatic…the car never cut off, it was still on, I will have the transmission fluid check and report back to the findings, I am not sure when the fuel filter was changed

I strongly recommend that rather than simply having the transmission fluid checked you describe your symptoms as completely as you can to the shop and let the mechanic troubleshoot it. Your goal isn’t to be sure the tranny has fluid, your goal is to get the car fixed. It might be low tranny fluid and a tranny problem, but it might also be something else.

I had the transmission fluid checked, it’s fine but the mechanic said it could be th e cat converter clogged but he will have to keep it and drive to let it get hot enough to see if he can get the car to acted up because when he drove it, the car did not act up

OP, still waiting for you to clarify “Lost ability to accelerate, but never lost power.”

How does a car with a clogged cat converter run fine when cold but act up when hot???

@BillRussell, I really can’t explain it (I am a female and knows nothing about the mechanics of a car) the car never shut off, I was driving and all od sudden the car lost the ability to accelerate, I was pressing the gad peddle and the car would not go, after a couple of minutes it picked up speed no more than 30 mph

@insightful, I don’t know the function of a cat converter, what exactly does it do?

The catalytic converter contains a honeycombed structure of catalyst to convert pollutants in the exhaust to harmless gasses.

I thought her original description was that the Prius although failing to accelerate the gasoline engine would continue running but not get much above idle when the accelerator was depressed. Does this vintage Prius have throttle by wire. I am a little past 5 years driving my first TBW and hate the intermittent off idle “dead spot”. My Kia will restart and then drive normally until the next time. OP’s problem could be something like that but I would also likely suspect fuel or cat malfunction.

The OP has a 1998 PRIZM - a Chevrolet product

Does the engine sound strong and smooth when it won’t accelerate? If the cat is clogged, the engine will struggle and bog down. If the transmission is slipping the car won’t accelerate, but the engine will rev without going anywhere.

@knfenimore , the engine is I guess is still strong and smooth

Granted the details are a bit murky and without having hands on the car anything I say will be a wild guess at best, but I wonder if the transmission is dying?
I know there were some issues with transmissions on this vintage of PRIZM and at 17 years of age it just may be due.

You could try a converter stall test which will reveal any slippage in the clutches in the transmission.
Set the park brake. Hold the foot brake.
Shift into LOW and try to rev the engine quickly. You should feel the engine bog around 2000 or so RPM I think it is.
Allow the engine to idle for a moment.
Repeat the process in SECOND.
Allow to idle for a moment.
Repeat the process in DRIVE.
Allow to idle for a moment.

If you see the engine revving to 3000 RPMs or so during any of this the trans is likely dying.
If you do this test, when you rev the engine do it quickly and do NOT hold the pedal down. Do NOT repeat this test over and over either because a transmission can be damaged if the test procedure is abused.

I’m kind of guessing at the converter stall speed as I do not have the specs for a PRIZM so those RPMs are a general guideline only. Hope it helps.

I’m going with tranny dying.

The Chevy Prizm is a Chevy/Toyota product, basically it’s a Corolla. It is possible a cat could be clogged in certain situations and not others, heat related for example. The stuff inside could have dislodged and be moving around for example, and when it gets in certain orientations it partially blocks exhaust flow.

I had a Saturn automatic transmission and it done the same exact thing. My car would not get over 30 or 35 mile per hour and it seemed like it wasn’t wanting to shift into a higher gear. It turned out to be a rely sensor on the transmission. I hope this helps you.