pbink

Okay honda-acura, I've done a CRAP-TON of research to find out how I can get rid of my slight plusating rough idle (sits at 800 +/- 50), it's not that bad, but drives me nuts and gets way worse when A/C is on at red lights. Also hoping that these fixes will get rid of my faint clicking/sputtering sound while accelerating...

This weekend here's my checklist of things to do before I go postal...

1. Burp/bleed coolant from both thermo valve and radiator cap
2. Check all vacuum lines for leaks (man this seems almost impossible to do w/ 100% accuracy)
3. Seafoam that sonofabitch
4. Change the oil myself and top off all fluids
5. Change spark plug wires w/ new NGK OEM ones (plug wires & coil wire...just replaced plugs w/ OEM NGK ones)

Any other suggestions before I start buying valves, O2 sensors, etc...?

98CoupeV6

Distributor cap is the only other thing I can think of. Seafoam should do it though...it did the trick for me when my idle was pulsating like yours. If none of that works it might be a clogged EGR valve. Also, have you changed your PCV valve lately or cleaned out the throttle body? Although I guess that wouldn't affect the idle since the idle air comes in through the idle air control valve (aka a hole with a screw in it).

pbink

thx for the quick reply...sounds good. I should also just have my timing checked for shits/giggles...what's a good price to have timing adjusted at a local shop? (never had it done before)

98CoupeV6

If it started right after a belt change then that could be it but I doubt it. Leaving the belt misadjusted by one tooth will result in noticeably poor performance and two teeth will probably screw some stuff up. Do the other stuff first

BNaccord2k1

How about checking all the motor and transmission mounts?

pbink

Well just did the seafoam to see how that would affect it...I'd say, if anything, it made the idle a little worse. I want to say acceleration/response felt a tiny bit better, but the idle now surges a little more than it used to...

After car warms up (or before, really makes no difference) and I come to a red light the idle sits a hair below 900 rpm. It will sound perfect for approx 1 second then drop a hair for about a half-second then it seems to overcorrect by a hair in the opposite direction for a half-second then settles back to 900 for one second...loops like that over and over.

The total amount of surge/drop is less than 50 rpm total (+/- 25), but the mother shakes quite noticably even with all acessories off. I'm worried it's just shaking shit loose all over the car.

I sprayed carb cleaner in the PCV valve (that's the one coming out of my valve cover, right?) and that didn't help any either. Cleaned the ICV but it only helped a little. I'm almost positive the sputtering during acceleration and the pulsating/rough idle are related. I'm hoping the timing's just off by a tooth...what would that feel like? Also, if the belt's on correctly, could it be the positioning of the distrib or would it be a dirty/broken distrib? Thanks in advance man

pbink

doubt it...the idle is surging/droping quite noticably...I don't think mounts would cause that. thx though.

98CoupeV6

Well if seafoam made it worse (assuming you used it correctly...you should have also put 1/3 in the crank, run it for a few miles, then changed the oil), it's probably an ignition/electric/fuel delivery problem.

Change your spark plugs! The condition of those alone (try to take pics) will tell us a lot about what's happening. Also, just change your PCV valve - they're only like $7 at auto parts stores.

If it sputters during acceleration, check out the EGR cleaning FAQ I posted...it has some troubleshooting stuff in there. But do all the easy/cheap stuff before you go replacing your distributor and wires.

pbink

Okay 'nother update...

Today I wanted to get all the seafoam outta my oil from yesterday's engine cleaning, so I changed the oil/filter. I put brand new NGK plugs, topped all my fluids off, and put on a new PCV. While I was under the hood, I checked all the distrib connections by just pushing on them. I dunno what exactly did it, but now my engine idles 100 rpm higher (@ 1000 +/- 100 which makes it shimmy less) and the pulsating surge is basically gone. I had the new plugs in there before the seafoam and oil change (oil had been changed recently anyways) and the idle was way rough and surgy, but the combination of new plugs w/ seafoam treatment, oil change immediately after, and new PCV seemed to have gotten rid of the surging almost entirely. I did use 5W30 and have no idea what the old oil was...maybe the thicker oil could that have raised my idle by 100 rpm?

BUT...that idle's still too high (would like the stock 750 +/- 50) and I still get the clicking/muffled thuds while accelerating quickly. While she was idling, I got out and put my hand in front of the tailpipe and could feel a steady rythmic exhaust pressure, but every couple seonds it would miss one and then fire two quickly together, out of sync...then run normal for another couple seconds.

Tomorrow I'm going to get a timing light and make sure my pointer is at 15 degrees +/- 2. If that's fine, I'll do a valve adjustment. I'll also take off the distrib cap, but I'm not quite sure how you tell if it's bad or not. I wish I had a voltmeter so I could check the plug wires, but if wishes were fishes...

Again...thanks for all your help!

98CoupeV6

You're not getting a CEL and you're misfiring? That's odd.

I think a lot of your troubles have to do with a dirty EGR valve (if the dist cap is fine). But it should be one of your last steps since it'll take a couple of hours by itself. If you adjust the valves you could fool with it then since you'll have everything off.

Maybe just lower the idle by the screw (I think yours have screws) and call it a day? :dunno: If your valvetrain isn't ticking during acceleration adjusting the valves might be overkill IMO. Keep up the good work and let us know!