I just bought this 97 Civic Ex a couple of weeks ago. Since, I have changed the spark plugs, wires, rotor and distributor cap. It has ran great up until this morning. When I was in 4th gear doing about 60 mph, it starting losing power and wouldn't pick up speed. When I gear down to 3rd it seems to run just fine. Put it back into 4th and it loses power again. Anybody have any ideas what might be going on?

 

sounds like a short in something or lose connection. does it do it in low rpms in other gears. like shift from 1st to 3rd and give it gas does it go or does it lose power.
i dont think its from being in 4th gear.

cel?

 

I'll have to check it out later(at work now), but I don't remember anything odd happening until I got it into 4th. I didn't think it had anything to do with 4th gear, that's just when it started losing power so I thought I should mention it.

no cel

 

Check the timing-- cam timing and spark timing. Something is seriously wrong. On a level road, you should be able to run 60mph in fifth gear and pick up speed.

 

Can the timing get off by itself? This car has run great the entire time I've had it. I had it doing 80 on the freeway the other day and it had plenty of power. I don't know if it's possible, but maybe I pulled something loose when I put in a new temp sending unit. That was the last thing I did before I drove it this morning. I don't see anything loose though.

 

Timing belt could have skipped a tooth. That's a common reason for sudden loss of performance. If that has happened, replace the belt immediately before it strips completely and allows the valves to crash.

You can check by taking the upper plastic cover off, you must loosen the valve cover and lift it up some to be able to get the plastic cover out from under it. Then rotate the engine by hand to TDC on the crank pulley and check the marks on the cam pulley.

Edit: Also, does the engine run smooth but just not "pull", or does it sputter and misfire?

 

Well, now I'm really confused. I drove it home and it was still losing power in 4th around 60mph. I took it back out to try all the gears at different RPM's and such. It's running great now and no problems in 4th. I got it up to 80mph in 4th and it had plenty of power. Could something be loose? I guess I'll have to wait and see if it does it again. Thanks for your help though.