Rough idle

[Zaurusman]

I have a rough idle in my '03 ES. I mean, I've felt it idle so smooth I could barely tell it was running. Now it idles slightly lumpy -- I'd expect that with a higher lift cam, but everything's stock. EGR looks pretty decent - somewhat dirty but not clogged by any stretch. Put in NGK iridiums - that solved it for around three days. TB was recently cleaned. Occassionally, it'll start, then drop a few hundred RPM, then recover. This happens much more often with the air on, and it hesitates when it's on sometimes too, like the powerband just got more granular. Doing 20 mph in a school zone in 3rd gear sends the head bobbing back and forth periodically; everything's so freakin' touchy. Launch in 1st with the air on like you would with it off and you'll bog. What's going on here? Also, it frequently "vibrates" when launching, like the engine mounts are bad - but the dealer just said they expected them to be bad but found they were fine. They also couldn't feel the obvious rough idle though...

 

[stephsnumoneguy]

same here

Same exact thing happened to my car. Took it to the dealer under waarenty all they did was run my damn idle through the roof it stopped for a while and now it is back again any suggestions anyone???

 

[B2600i]

Check the EGR valve to make absolutely sure it's closing completely. You can check by removing the EGR valve and putting a small amount of water in one of the ports and checking that it doesn't flow through into the other port. FWIW I've had two 2.0 litre Protege's with this problem in the last year. No CEL and no other problems. BTW the replacement EGR valve has been redesigned.

 

[WetsuitxNinja]

Maybe run some Seafoam thru the throttle body to clean the injectors? I think the bottle says 1\3 in the tb, 1\3 in oil and 1\3 in gas tank for full system cleansing. It smoothed my idle out, I just did the 1\3 in gas and 1\3 in tb....didnt feel the oil was necissary. Plus its cool to watch smoke pour from your exhaust.

 

[Diehonda]

Maybe run some Seafoam thru the throttle body to clean the injectors? I think the bottle says 1\3 in the tb, 1\3 in oil and 1\3 in gas tank for full system cleansing. It smoothed my idle out, I just did the 1\3 in gas and 1\3 in tb....didnt feel the oil was necissary. Plus its cool to watch smoke pour from your exhaust.

1.5 oz of seafoam per qt of oil in crankcase, drive over fifty miles and under 200. Change oil and filter. 1.5 oz per qt of oil sucked up in vacuum line to TB and have someone hold the idles steady and poor slow enough to not kill it but fast enough for it to not run right thru the system with cleaning the build up. Immediately turn the car off, let sit for fifteen to twenty minutes, turn car on and drive around between 20 and 45 miles an hour to burn off buildup and residue. Will be really smoky(whitish gray smoke). High mileage engines beware as it could make the internals clean enough to unclog a leak. half to full can of seafoam in gas tank, to clean injectors and remove moisture from the lines.

You can also clean the EGR manually with TB cleaner. What about testing the coils, replacing the plugs, replacing the MAF though?