I have been driving this 1997 Toyota Camry (Pencil Light) for 2.5 years now and it has served me quite well until recently.

The trouble doesn't seem very serious but i am afraid that it might get serious because it is strange. What i have noticed is that 30mins into start and drive, the speedometer suddenly stops working and the Mileage reader goes blank and the engine drops noticeably in power delivery i.e. to say, i have to push the gas pedal and ram to like 4000-5000rpm before it can maintain its acceleration. That moment of pushing the gas pedal only lasts for several seconds before the acceleration rather drops back to normal. Then the check-engine light comes on when it happens.

The acceleration drops almost back to normal (but not exactly normal because acceleration really does appear to require unusually higher rpm) when i am on a sustained speed like on a free way. But it suffices to say that I have noticed a marginally higher fuel consumption rate (like 20%) when this happens.

Then when i park and go for my daily activities and return hours later, the engine would show no problem, the check engine sign would be there but suddenly disappear while i am driving (apparently to show that everything is fine). Then maybe about an hour into my journey, the issue above starts again until I reach my destination.

Experts, please can you help? I have gone to scan but all the scanners are seeing is the ABS which has been there since i bought it and nothing more.
An elderly mechanic is telling me that it is an issue that has to do with speed-sensor and gear transmission bla bla bla. Can anyone in the house assist with an explanation? The car has been having this epilectic seizure for like 3months now and sometimes, when i drive for an hour, the epilepsy won't occur. Please help before it gets worse or something

Call 08030938491 if you are in lagos.