2003 Accord EX with 180000. I will do my best to describe the symptoms. At 15 mph, the car abruptly stops gaining speed. The car is sill running but if you press the gas, you don't gain speed. If you change to 2nd gear speed is regained but the same thing happens at 25mph. This happens again at 40 mph. Get into 5th gear and speed resumes and at 70 mph cuts out again and here is a strange hing, after reaching 70 and the power stops, when you reach 60 mph the power resumes??!!??
The things that come to my mind are:
Clogged fuel injectors
Missing (spark plug prob)
What else can I look at as a problem?

 

Get a check-engine light? If so, get it scanned & tell us the error-code number (not just the guy's description). If not, watch the bulb-check when you first turn on the key - the CEL should come on for 2 seconds then go out.

How old are the spark plugs?

Run some Techron (or your favorite fuel-system-cleaner) thru the fuel tank.

Other possibilitites like cam-timing actuators should throw error codes & turn on the CEL. Some of these type of things can set a low rev-limiter (limp-home mode) but they'll also trigger a CEL and error code.

 

Has this been an intermintent issue at first and now its all the time? If so had close to the same issue, clean the EGR valve. Mine was a mess car runs great agian and i picked up some MPG.