Paraphoe

Hey guys,

New member with a newly purchased used Civic. Was hoping you could help try to ID the source of a problem. Car seems to have trouble smoothly accelerating. Temps are OK, engine sounds fine. I'll get on the gas and it'll accelerate OK at first and then I'll continue feeding gas and it'll seem stuck around 2500 RPMs. I'll push the pedal down a little more and then all of a sudden it'll jump to like 3500-4000 RPMs and shift. It's like it's not recognizing the added "gas" and then all of a sudden wakes up and tries to compensate. I've also noticed a rough idle, where it's jumping from roughly 500 RPMs up to 1000, then back down, then up, etc - but it's not doing this all the time. Mechanic says it needs a tune, but there's gotta be somthing more going on here. Any idea on what this could be? MAF sensor? Fuel injectors?

Thanks in advance for any advice/assistance.

- Jason

Paraphoe

Annnnybody?

HLC

start by check your air filter.

CrewChief

iTrader: (1)

Jumping idle is only 2 things. Seen it a lot in civics.

Throttle posistion sensor or air idle control valve. only 2 things that cause that problem.

Here is a test. When the car is at idle and starts jumping up and down disconect the idle control valve. If it drops down and stops there is your problem. If not its the TPS.

livelife686

change fuel filter. my car had a bad shake like sputtering when i gave it gas, i changed fuel filter yesterday and OMG it made a huge difference. The sputtering is gone now. I tried blowing thru the old fuel filter and I couldnt at all, I turned it around and blew backwards (reverse flow) and brown and black trash came out of it, thats how clogged it was and causing car to run like [shizzle].

Try changing fuel filter. takes about 30 min max. its 6 10mm nuts and a pair of pliers for the 2 hose clamps and thats it. lmk if that helps, cause it helped on mine.

CrewChief

iTrader: (1)

Depends on the year of the car. If its a new civic the filter is in the tank and is not cheap cause its a whole unit with the pump.

Paraphoe

Thanks for the input, guys. Just to clarify, the car is a 1998 EX coupe. Let me just add some more critical detail here as I've found more about the issue - this problem is very odd.

Here's the thing I'm noticing - this is only really happening on very hot days. My hood is just a black primer replacement hood, so it's dull black and sucks up and holds a TON of heat, but my temp gauge is reading fine. Still, on my drive to work at 7:30 each morning, the car rides fine. But then it sits in the sun all day in the 95+ degree heat, and when I drive it home is when I'm having these issues. When it's cooler out or raining, it's never an issue.

The other thing I'm noticing is a very slight "wavy" or up and down acceleration pattern, for lack of better terms. Meaning the car is driving at 65 MPH or so and I can feel it lurch forward everrrrr so slightly for 2 seconds, then settle, then lurch forward again, then settle, repeatedly. I've also noticed this happen a few times when trying to shift - the RPMs will bump up slightly, then drop, then bump higher, then drop, then bump a little higher and finally shift, all while I hold a steady foot on the pedal.

This is a really odd pattern, and I haven't much of an idea what the issue could be. It's nothing I've seen/heard about in any other vehicle. If it's heat related, what could the heat be affecting? The engine performance itself? With this new info do you still think it's the TPS or IAC? My air filter is fine, but that's about all I've checked.

Thanks for reading, and I appreciate the help so far.

- Jason

Scrappy30

I am having a similar situation.

I just had the following items replaced on my 97 Honda Civic LX:

Head Gasket
Water Pump
Timing Belt
Timing Belt Tensioner

After about 1 month, I am getting a loss of gas mileage and horsepower (from 29 MPG to 24-25 MPG). Also, my car is revving up to about 2000 RPMs at certain times of the day when stopped in traffic or at lights.


I have 2 questions.

1. My car was revving up to about 2000-2500 RPMs before I had the head gasket replaced (the car was overheating but has not since replacing the parts above). The mechanic said that the head gasket replacement should take care of this but it didn't. The car only does this during hot temperatures outside between 11 A.M. and around 7 P.M. When I go to work in the morning, it does not rev up while sitting in stop and go traffic or at a light. It will do it if I run some errands during my lunch break and on the way home from work.

Does this sound like my idle control valve? I figured I could clean it first before replacing but I wanted to know if anyone had experienced similar symptoms.

2. Does anyone know why I would have lost gas mileage and horsepower? Is my timing off? I didn't have this problem before the replacement work was performed. I'm not sure what I need to check first in this case.

s0yp0p

Try changing air temp sensor since its over heating. It could be sending the wrong code to the computer and overheating.

Paraphoe

I wanted to post a follow up here. I traced my problem to the air conditioner. When it's on, it drags on my engine and totally messes up the RPMs. I'm not going to worry about it till next summer.