I've owned my 95 prelude vtec 5 speed for 1 year. In the past 3 - 4 months, I've noticed my RPM has decreased when at my usual cruising speed. At 80mph, my RPM is at approx. 3000 (whereas it used to be a normal 3500, easy). Even pushing the speed limit to 90+ mph only increases my top RPM to barely 3300? I can't reach 4000 - 5000 RPM without feeling like I'm really "pushing" my engine to its limits...! My car "feels" normal -- no pinging, knocking, tranny feels smooth and by all other interpretation, my engine feels "strong". I just don't understand why the sudden loss of power?
even out of 1st gear, i can't rev my car past 3000 RPM. I usually go to 2800-2900 RPM before having to shift to 2nd gear... and every gear is the same -- my RPM does not spike past 3000 unless I press the pedal to the floor (which I am reluctanct to do, since I do not wish to stress the car; plus it used to drive normally before).

I've taken it to a Honda dealership where they ran diagnostics and they told me the computer chip did not return any errors with the car. They did find a crack in my header.

In the past month - I've replaced my cracked exhaust manifold. It did not increase my RPM. I also replaced my catalytic converter (it wasn't clogged like I expected, but I put in a new one anyway hoping it would help). Nope, it didn't help. I've even replaced the clutch (which just happened to go out). That didn't improve the RPM problem either...

Another weird thing is: about 2 months ago (before i fixed anything), I was driving to work and the problem miraculously CORRECTED itself! For my entire 15 minute drive to work that morning, my RPM was back to normal -- i could accelerate quick, punch my gas and see my RPM needle easily spike past 3000 - 4000, EASY. Then when I hopped back into my car later during my lunchbreak, it went back to being all f*cked up again! It's never improved since... what' sup wit dat?? I'm so confused... My resting (idle) RPM also seems a bit high (at 1500). It used to be 500 or so before all this began...

What could be the problem? Is it the O2 sensor? Is it my aftermarket cold air intake? my timing belt? I don't know where to look next -- running out of patience and money!

I CAN'T POST MORE THAN 5 MSG PER DAY? how do i change my member settings? do i have to pay or something? i'm getting helpful IM's and replies... unfortunately, I'm unable to respond??!

also - what are the known symptoms of an old timing belt? could i possibly be a case study? (i've yet replaced mine in the year i've had it. it's got 150k miles on it)


Modified by pkprelude at 4:04 PM 5/8/2003

 

not sure if it helps but i had the same problem years ago in an integra and a few shops couldn't figure out what was wrong...finally one auto repair shop figured out it was a bad distributor... the car just would rev past 3000-3500 rpm.

 

Since the gear ratios are fixed (i.e. dont change) there is no physical way X mph can equal one rpm on a given day and then Y on a different day.

The only way this is possible is by changing the gear ratios or putting a bigger wheel/tire combo on the car.

 

this is the 2nd post about the same thing.

 

maybe you have a 6th gear...

 

maybe lack of horsepower...

 

he is right you you can't just have one rpm make x amount of mph and then suddenly change i would look at a faulty guage or wiring. Or distributor