MAVTS2k

Hi...pretty new here. Just bought my first S2K a couple weeks ago and am enjoying learning all I can. The car is a 2000 Seabring Silver with 150k miles, all original (no mods). Been my dream car for 15+ years and finally pulled the trigger on one this summer. So far I am happy I did!

I've noticed that the car frequently appears to idle a bit rough and I can't figure out why. It seems worse when the car is semi-cold but also sometimes happens when car is fully warmed up. The idle is right where it should be, doesn't dip too low, and there is no hesitation or any other issues when accelerating. There is just a very slight "skipping" feeling sometimes when idling that doesn't feel normal to me. I have felt the car run smooth at idle so I don't think this would be considered normal. It feels almost as if there is a very very slight misfire. I am not getting any CELs. I don't notice the engine shaking visibly when looking at it. Compression tested fine (210-215 all cylinders on cold engine). I also bought a new OEM coil pack and swapped it out on each cylinder but still had the same problem.

Seems that the IAC or MAP issues people frequently talk about also resulted in hesitation or a jumpy idle which i am not experiencing.

Is this just how these cars are?

blueosprey90

I'm no big expert, but until you have more significant symptoms or codes, I think you'll have to assume it is normal. I have a 31,500 mile '04 that idles at about 900 rpm and it has a roughness that is not present at say 1,100 rpm.

A lot of people take their car to Billman for a once over and for mechanical work. He is on the eastern tip of Long Island, but maybe you can take a ferry over from New Bedford or somewhere in Rhode Island. He's a wizard, but not inexpensive. Billman is on the New York Metro boards. But there have to be guys in New England as well. Do a search of the New England forums.

Welcome and good luck!

autofan01

Brand of gas seems to effect this sometimes. mine has other problems but for a while any time i filled up on base the idle would give me grief. Cleaning up the map and IACV are stupid easy.

Dont brush any of your concerns off as "oh i guess thats how it is". i felt that my valves where a bit on the noisy side and was eventualy convinced that thats just how it is... until a cel convinced me to do a compression test and suprise exhaust valve guides are shot! just after i purchased a brand new bride vios3, rails, ap2v1s, and conti extreame sports.

MAVTS2k

Just an updated, i replaced all coil packs and cleaned the IACV per Billman's procedure. Problem is still there.

What I am noticing now is that this issue is most prominent before the engine is fully warmed up, meaning within the first 5-10 minutes of driving the car. Once good and warm the idle is smoother although a very slight "skipping" feeling is still present.

Would something like this be cause by a valve adjustment issue? Thinking maybe it is just on the edge of being out of spec and once the car warms up the expansion of the metal changes the clearance enough to ease the issue. Does this make sense?

I don't have the bent feeler gauges, gaskets, and adjustment tool needed for an adjustment right now so I wanted to get some feedback before purchasing all this stuff.

Orjinal

I've had a similar issue and a valve adjustment made it go away. If you're in MA, its worth to take it to Billman for a once over.

ps. Sebring Silver was first offered in year 2002. For the year 2000 the only silver offered was Silverstone.

MAVTS2k

Thanks. Already have plans to see Billman in Aug for a clutch. Trying to get the idle thing sorted on my own.

Also good catch on the color mistake...I realized afterward that it was the incorrect color but couldn't figure out how to edit the post.

windhund116

New spark plugs? Just as a rule-out.

Thanks!

twohoos

Try a new MAP sensor. I had the exact same symptoms a year or two ago and a new MAP not only cured it, it made every aspect of engine response smoother. The original F20C MAPs were troublesome buggers anyway, even when they were working; but they also seem to degrade with age, and at 20yrs/150K yours has definitely seen better days. They're about 80 bucks online.

MAVTS2k

Another update...got all the tools and did a valve adjustment. Exhaust was tight and out of spec and intake was loose. Very tight to work in there but the go/no go method served me well.

Seems to run smoother and quieter at idle but did not solve my rough cold idle issue.

Next on the list is spark plugs and new map sensor. And I will try cleaning the iacv again. Might also run some fuel injector cleaner just in case.

MAVTS2k

Any thoughts on aftermarket map sensors? Looks like they are about $30. Are these any good or waste of time?