Poor perfomance when load placed on engine

I have a 2000 Toyota Corolla LE that ran very well until about a month ago. It has about 146,000 miles on it. A month ago it started hesitating from a standstill and the engine ran extremely roughly when trying to move the car. But when I put it in low gear it did much better, although not great! When in Drive it barely moved the car at all and would frequently stop running completely.

When I took it to an auto parts store they hooked it up to their computer and it read out that I needed either spark pugs, spark plug wires, or a new coil. I have replaced the plugs, but that made little difference. I then took it to another auto repair place that told me that it was either a problems with valves, or a ‘problems in the lower engine’. I don’t know what that latter problems means but either way it sounds like it will be very expensive to fix.

Since the car is 14 years old with almost 150,000 miles on it I question if it is worth the 1200-1500 dollar estimate they gave me. The other thing that makes me pause is that it runs just fine some times.

Does anyone have some advice or ideas of what it could be, and what do you think of spending that much on it?

What they actually read out of the computer was probably a set of codes indicating that the car was misfiring (P0300 to P0304 - all or some). Having a misfire code doesn’t NOT tell you what you need to do, like replace plugs or wires etc. It just means that in one or more of the car’s cylinders the fuel air mix isn’t blowing up.

This can also come from poor compression - and it sounds like that’s what you have. I will have to guess based on what you said about the shop that they did check the compression. This would have been reported as a set of numbers - one number for each cylinder, or 2 each if they also did a “wet” test. So look at your invoice and see if they reported doing a compression test and if they recorded the results. Post the results.

Also post the actual error codes if you still have them and some basic info on the car’s maintenance history. A car can run poorly for 100 reasons and many of those are related to neglected maintenance, so report what you can about that.