Diagnose these symptoms ...

These symptoms are more noticeable on a cold engine, although it still does it when warmed up.
Not sure if these symptoms are inter-related.

  1. When idle (@operating temp), the rpm’s tend to fluctuate by about 100rpms or so, it isn’t much, but at times the rpm will drop for about 1sec and car seems to catch it and bring it back up to norm. It would fluctuate (and rise back up) like this every 4secs or so.

  2. When holding the RPM at around 1.5K, the exhaust will blub and gurgle sporadically. It doesnt do it when I hold the RPM above 2K. I’m thinking this isnt normal though.

  3. Sitting in neutral, I rev the car, and when i let off, the revs will drop below to around 200rpm (almost stall) and then rise back up to 700rpm.

My engine is basically stock, just changed the spark plugs and timing belt few weeks ago.

I hope someone can tell me whats wrong with the car, and what i should be checking.

TIA

vacuum hoses, pcv valve. get a haynes manual from pep boys and go through the troubleshooting. also download the helmes manual. try a search in teh archives section

I’m experiencing the exact same problems here!!! maybe a little less RPM drop, but very similar!

Thinking O2 sensor or CTS(coolant temperature sensor)…

The first to find a cure tells the others! hehe!

Originally posted by Answer
[B]I’m experiencing the exact same problems here!!! maybe a little less RPM drop, but very similar!

Thinking O2 sensor or CTS(coolant temperature sensor)…

The first to find a cure tells the others! hehe! [/B]

Well I’m glad i’m not the only one facing these symptoms.

I always thought a vacuum hose leak would cause more idle fluctuation that just a 100rpm or so. But who know, I will look at that and the PCV, as XDeep suggested.

Whats a good way of checking for leaks though?

I wanted to replace all my vac hoses yesterday with some red silicone hose to make sure I have no leak, but when I saw that the kit was 60 bucks, I changed my mind! :uhoh:

I think i’ll simply replace all the hoses with some regular vac hose to see…

Automatic transmission?

If you’ve got an automatic transmission, check the EGR valve

I’m thinking it’s the o2 sensor as well

Originally posted by VTC_GsR
I’m thinking it’s the o2 sensor as well

Shouldn’t the ECU throw a code if it’s a faulty O2 sensor?

Originally posted by joeygill
[B]

Shouldn’t the ECU throw a code if it’s a faulty O2 sensor? [/B]

no, the sensor can be bad but the ECU won’t know it unless the sensor completely stops working. The O2 sensor can work and throw false informations…

Actually it should throw a check engine light. The o2 sensor is either good or bad. Your car will still run but it will stutter like a 6 year old kid. The code for the sensor is 1

i got a code1 (o2) but a new distributor fixed that. i even tested the sensor and it checked out ok. guess ill check the egr tomorrow too

Did anybody fix the problem?

save your money its not the o2, eacv electronic air control valve, dealer only part $270, still havent changed mine cause thats just way to f’n much

hey

i have the same exactly problem my car when i will start it it will go at 1700km and go down to 500rpm and go up again after 6 or 7 time he will stand at 1300rpm, any help will be appreciated

timing belt

Since you changed the timing belt I would make sure the cams line up. I say this only because I’ve seen it done. If one of the cams are one tooth out of alignment the car will run but not very good at idle.
Peace,

Crazyteg : Actually the idle does not fluctuate as much as yours does, it is very mild indeed.

Tsarya : I did the timing belt change myself, and I know what the idle is like when it isnt lined up right, this is definately milder than those symptoms.

I’m gonna try cleaning out the TB and IM (as much as I can reach in there) and see if that helps. Also, the symptoms happen periodically, its not always there.

hmmm

mine is was start do it periodicaly but now since 2 day is start do it more longer then before but i check like 15 minutes ago and the rpm go to 700rpm to 1600rpm i was a litle bit exagerated. and after stay at 1200rpm and i can heard my exaust made a litle noisy sound like blurb blurb…, someone tell me that maybe is my fuel pump or my fuel filter. Oh maybe that can help you guys understand my problem like 2 days before some gaz leak from somewhere under the hood.:sad:

I have had the same problems since december. I am taking it in tomorrow to get it fixed. My symptoms; fluctuating idle, doesn’t start in heat, no power in high RPM’s, really loud and throaty at high RPM’s… I’ll post on monday or tuesday with what’s wrong.

if your rotor is beat it won’t idle well. if it has a lot of play while its still on the shaft. fixed my prob.

chsscott

i will waiting for ur post chsscott:up: