A slight "stumbling/hesitation" sensation

Maybe somebody can help me. I have a '97 Toyota Tacoma, two-wheel drive. It has 154,000 miles on it. During the last three weeks, there’s been a hesitation/ stumbling sensation happening occasionally in the first three gears. It doesn’t happen in 4th or on the freeway. At first, I thought it felt more like a “slipping”, like a clutch going bad (since I still have the original clutch). I had my mechanic check it out, and it’s fine. Here’s a brief history of recent work done. Three months ago: injectors removed and cleaned out on a special machine. I replaced the cap & rotor and spark plugs. The wires were replaced last year. I replaced the fuel filter and PCV valve. I cleaned out and replenished my K&N air filter. Last week, I checked the connections where the spark plug wires connect to the cap. They seem fine.

Any suggestions?

The K&N filters use oil and this collects on the MAF sensor. Try cleaning it with sensor safe cleaner. I know, because K&N gooped up mine. A new one not a replenished one. Make sure that you let your K&N sit and congeal before you install it.

I agree with @knfenimore . . . sort of.

I believe you should go one step further

Get rid of the K&N air filter

Put the stock filter and housing back

& ask you mechanic to double check the EGR valve.