I have 1999 civic, and when driving (some of the time) or in park (always), it won't rev past 5000 RPMs. As it hits 5000, the engine noise lowers, and it cycles 5010/4990 back and forth. If you press the throttle more, the cycle up/down speeds up. Initially the cycle speed is about .5 secs, the faster rate is .25 secs.

Otherwise the little 1.6 liter engine is running great, plenty of power, but it just can't climb the 7400' pass at any respectable speed anymore (used to do 70, now 45), it just seems like a rev limiter or governor is kicking in. Usually have to go over at about 5500-6000 RPMS, now you have to pick a gear that keeps you below 5000. It's a steep pass, and it's driven 4 times a week (twice over a day).

A flat out acceleration from 0 to 85 is completely fine. There are no indications of anything odd or slowness. There is what I would call a minor pinging type noise, but it's not my car - so not sure if that's normal.

No check engine light (and the light works). Mileage is about the same as it was when it worked before. 170k miles. I pulled the O2 sensor wire, and it posted the correct code. (I have a little scan computer - Scangauge II). Everything seems fine on it.

Fuel filter was just changed. And it's serviced (oil & such) regularly. Timing belt was about 60k miles ago.

Any suggestions of what to do or what the problem might be? (The closest dealership is 220 miles away, so i'd like to help these folks out - driving over that pass is requires to get to the dealership).

 

First thing that comes to mind is limp mode....? Is the ECU fine?

Not sure though. This isn't my hottest topic...

 

limp is around 3k, thats not it.

when a cars is not getting is desired fuel it will cut out. check fuel psi

 

Ah I remember reading about limp mode being around 3K but wasn't sure and figured I'd put it out there anyways. Thanks for clearin that up for me .

 

This same thing happened to me and it turned out that my cat was clogged it would do the same thing felt like a rev limiter and i removed the cat and i couldnt see through it changed it and my problem was gone

 

Alright then, I will try the exhaust system, see if it's clean, and then the fuel pump.

As an update, I found out that if you put the car under load (IE reverse with brakes on) it will die out at 900-1500 RPM. Also noticed that under either condition (load or just nuetral at 5000 rpm), the fuel flow before it cuts out is 10.8 Liter/Hour, then it dies. (I love trip computers) To me that says "FUEL" because the input number (fuel) is the common condition for both situtations. I'm pretty sure the exhaust gas volume will be different for each condition, since wide open (5000 RPM) in neutral puts the ECU in OPEN LOOP, while under load (1200 RPM) it's CLOSED LOOP. I think that elimates the exhaust...

Any comments before about the fuel pump idea before I go buy one for $200?

Thanks