Yesterday, I started having a new problem with my car (93 Accord EX automatic). When accelerating slowly (for normal city driving) I would slowly increase the pressure on the gas pedal. Instead of accelerating in the usual way, the speed would level out around 20-25mph. In that range, the speed would increase, but only very slowly. When I pressed the gas pedal down some more, it seemed to have almost no effect, until I pushed it pretty far, at which point it would give a big burst of power. In short, there was either almost no acceleration, or else tons of acceleration, with little in between.

This didn't happen every time I stepped on the gas. Also, it seemed to happen more when the engine is cold; after the car had been running for about 10 minutes, it barely happened at all. It's cold and wet and snowy here in Wisconsin, if that matters.

Any ideas of what the issue is?

 

You may have an issue with the TPS (Throttle Position Sensor). This is the component which signals the ECM that you're requesting 'Mo Power. Over the course of time it wears (often unevenly) in that very small portion of it's entire range that corresponds to average throttle usage; in effect a "dead" spot. Everything's OK at idle and slightly off idle, but when you hit this worn area the ecm "sees" no value changes until you get past that 'dead spot.
If you're not experiencing any skipping, farting or otherwise offensive engine behaviour, I'd start there first.

P

 

Thanks - I'm not running into any other engine problems, so I'll check it out. Is there anything in particular I should look for with a visual inspection?

 

It looks like this:



And it's mounted to the side of the throttle body. As you can see, there is nothing to check.
It's normally diagnosed (and adjusted) with a multimeter.

P