Hello, I have a 91 civic dx. My problems is, when I'm driving I experience acceleration problems. Its not the transmission, gears change OK. It feels like the car is choking, I step on the gas hard and it kicks out but goes right back to choking a min later. Has a new distributor, plugs wires, fuel filter, new catalic, exhaust pipe, muffler, tried different PC, but nothing helps, was told the fuel pump is OK. Everyonce in a while the car would not start, based on what I've read so far it sounds like that main relay is bad, but would changing the main relay solve my acceleration problem? When the temp sensor or throttle body is disconnected the veh runs fine with no acceleration problems, but both of these sensor are fine, I've had them tested, 2 mechanics have looked at the veh but could not figure out what is causing the acceleration problem I'm hoping the main relay would fix it. From what I could tell the problem is worst in the winter when its cold, need feedback please, thank you

Check your MAP sensor, which controls timing (similar to old vacuum advance on distributors) and air/fuel mixture, depending on manifold pressure changes. Check the electrical side of the MAP sensor (Code 3) and the vacuum side (Code 5). Even if no codes are thrown, thoroughly check out the sensor--it's that important.

It couldn't be your main relay. They only make problems when you try to start the car.

How old are spark plugs?

Will give the map sensor a shot, will update you guys once results are back. Thanks

Plugs are about 1 yr or bit more

I forgot to tell you guys, when a diagnostic was ran on the car, it came back with a code 16, this is what lead me to believe the relay was bad. I forgot what the code 16 means but the mechanic at the time said he cannot explain the 16 because everything was fine from what he could tell

Code 16 is fuel injection system. Have you tried getting another set of injectors (for free from a friend or something) and try them out for a few days? Only injectors from another DX will fit you.

Test them with an ohmmeter.

Will also try the different fuel injectors. I spoke to a mechanic today, he worked as a hoda mechanic for over 20 yrs he said, I told him about my problem, he thinks it's the igintion coil and igniter, what do you guys think? I get different answers for different mechanics. Thanks for you feedback

When you replaced your distributor, did you check your timing afterwards?

Yep the time was checked, I changed the map sensor and nothing, engine sounds much better but still has acceleration problem. I was told to change the throttle body. What do you guys think, am I just wasting my money?

1. Are you using NGK plugs or cross-reference plugs? My experience is that NGK plugs work, by far, the best in Hondas.

2. Did you get 5 volts going between the ECM and the MAP sensor connector's reference wire? Did you test the vacuum side of the MAP sensor? Are the vacuum hoses themselves in good shape? Check the port that the MAP sensor vacuum hose goes into, on the throttle body, to make sure it is not clogged. Clean it with a very fine wire and aerosol carburetor cleaner, if necessary.

3. Did you check out the throttle position sensor? After the MAP sensor, this is the most likely to cause problems.

4. If all of these check out O.K. I'd focus on a possible bad ECM. Your Honda is 15 years old and many ECMs don't last that long. Try substituting a known good ECM. This would tie into the starting problem, as well.