Hey guys, I'm looking for a little diagnostic help:

1998 Civic EX Coupe
115,000
5 speed

If I rev the engine anywhere between 1500-3000 rpms it revs up and then drops back to 1000, and continues this cycle indefinitely. This happens in neutral-3rd under 30 mph.

Over 30mph there is no response until at least half throttle when it surges to 3000+

Anyone have any ideas?

6/22/2006 3:05:22 PM

iac

6/22/2006 3:09:00 PM

It idles perfectly. It's only when applying throttle that it cycles.

Why would the IAC cause that?

6/22/2006 3:11:13 PM

Check engine light illuminated? Go to Advance and have them pull codes.

6/22/2006 3:17:10 PM

stuck or sticking, could also be the tps, or maf, if people could describe problems on the internet, and have them diagnosed, then there owuldnt be a need for mechanics would there?

6/22/2006 3:20:55 PM

^What he said.

6/22/2006 3:21:58 PM

Obviously, but I can't get a mechanic around here who can tell me anything. I was just looking for possiblities.

No check engine light.

6/22/2006 3:25:23 PM

Is there even a MAF on civics?

6/22/2006 3:26:17 PM

do what now?

6/22/2006 3:29:44 PM

theres a lot of damn possibilties, too many for me to list in an hour, i would check mechanical shit first, throttle cable, linkages and plate, then iac, then the tps, and finally the map, more than likely in the course of checking things in that order, the problem will become painfully obvious

[Edited on June 22, 2006 at 3:33 PM. Reason : map i meant, god damn fruedian typo]

6/22/2006 3:29:54 PM

Yeah, I checked mech stuff first. My next was going to be the MAP and the TPS...

I was just hoping someone had run into the problem and could save me some time...

6/22/2006 3:36:21 PM

still guessing iac

6/22/2006 3:37:34 PM

Thanks, I'll break out the manual and see how to go about checking it.

6/22/2006 3:46:03 PM

Have you done the obvious and taken off the distributor cap and checked the terminals and whatnot inside?

What do the spark plugs look like? Wires?

The last Civic I looked at was a '94...owner was complaining about a missing/bucking/no power issue. The center terminal of the cap was total shit. The dizzy was full of rust. I had to take the damn distributor out and pry the rotor off with two sizeable pry bars (YES I took the screw out first ).

Another issue is the coil. I've already replaced two of these coils. One on a '95 and one on a '96. But you usually get a no-start issue there.

My guess is one of two things: (1) you've got an ignition issue...and a lot of times part-throttle power suffers because of the density/scarcity of the fuel mixture in the chamber... or (2) you've got some fuel pressure issues.

On an OBDII car, I'm surprised you don't have an MIL...

6/22/2006 3:57:56 PM

spray it with some carb cleaner...maybe its a dirty sensor.

What about a vac leak?

6/22/2006 4:14:20 PM

I had a Ford truck that would pop and backfire when under load because the coil would heat up and the resistance would build. I checked it when it was hot and found that the resistance was way out of range. a new coil fixed the problem.

6/22/2006 5:28:59 PM

change distributor cap/rotor/wires first. It probably needs to be done anyway.

6/22/2006 9:03:49 PM

throttle position sensor

6/22/2006 9:24:57 PM

does Honda not have any codes for a bad TPS or something? I know my Mk III supra throws codes for about anything EFI related... I've got a knock sensor code, MAF code (probably why it won't run right now), IAT code, and some other knock sensor related code.

6/23/2006 12:52:45 AM

honda will indeed throw codes for TPS, MAP (it doesn't have a MAF), O2, CTS, crank angle, TDC, etc.

And it's an OBDII car so the goddam ECM should tell you something, even if it's something like P99999, meaning "how the fuck should I know what's wrong with me?" (in jest, mind you)

6/23/2006 1:31:03 AM

does the CEL come on at all?

6/23/2006 2:04:18 AM

Never seen the CEL come on.

6/23/2006 9:30:28 AM

i thought a 98 had coil packs and not a dizzy?

6/23/2006 9:42:35 AM

go to the honda dealership, someone there will hopefully be able to fix it, if not i guess you're screwed, buy a new car

6/23/2006 9:53:38 AM

^^It does have a distributor...

6/23/2006 4:52:10 PM