Idles rough and rpm vary and almost dies - 1993 Toyota 4Runner

Marvin

• 85242 Answers
• Posted on Nov 04, 2008

SOURCE: idles rough

Check for engine vacuum leaks, most likely around the upper intake manifold arear, look for vacuum hoses that have come off or a missing vacuum port block off cap at the rear of the engine drivers side, large cap.

SOURCE: 87 Supra idles rough and dies out

I would suspect a vacuum leak. At idle under high vacuum the air fuel mix is being leaned out until you have misfiring so bad the engine quits. The exhaust smells rich because even a lean mixture, if it doesn't light off, if full of unburned fuel. At road speeds, the vacuum is low so the engine doesn't care if there is a small leak somewhere. It is getting most of its air through the open throttle. Check all your vacuum lines but remember that even if every line is okay, it could still be leaking from an old cracked intake manifold gasket.

Dar

• 2007 Answers
• Posted on Jun 15, 2009

SOURCE: rough idle, engine dies and rpm's flucuate when

Vacuum leaks. Leaking EGR or plugged PCV valve. Faulty idle control sensor.

SOURCE: Rough/Low idle then dies.

is your check engine light on any longer ? also has your throttle plate ever been cleaned that can cause this symptom it will get build up on it and not allow correct idle ,you can clean it yourself ,rmove the big hose that goes up that goes up to your throttle body and get a can of deep creep sold at any parts house ,then spray the deep creep on a shop rag and by hand wipe out as much of the flap areas as you can ,its hard to get your fingers in there but be patient . but dont spray any thing down in the throttle throat it may cause more problems ,try the wipout of the throtlle area and see if it help your idle !

SOURCE: 2003 nissan sentra se-r spec-v, started idle

i had a similar problem a few months ago with my se-r. i went to the dealership and had them reprogram the ecm and it fixed it(its on the recall list for your car.) once i did that everything ran great.