surging rpm Options

[Joe_1985]

well i just noticed this tonight, after i drove my 25 mile drive home and parked in my driveway, I noticed that my rpm would float between 1000 and 700 very slowly.

so i got out and stood behind my car and listed to the exaust (its stock) and id hear the rpms slowly go down to about 700ish rpm , sputtering missfire, then jump back up to 1000ish, sit for a second or 2 then slowly fall sputtering missfire, then repeat.


when i got the car i changed the cap, plugs, wires, rotor button, cleaned out the intake manifold, and throttle body.

ill check the plugs in the morning.

it also surges up and down the rpm range if i hold the gas steady, does the same thing falls very slowly then goes back up.

btw this is a 7afe with 189,000 miles on it

[Joe_1985]

plugs are dry

did the tube seals

pulled all 4 plugs, they gave me the impression the engine is running lean.

cleaned em and reset the ecu, surge gone

drove around for a bit, still lean

timing is 2 degrees advanced


i think something may be amiss

only parts left to check or replace are..

fuel pressure regulator
injectors
o2 sensors
egr, i had this mess up on one of my celicas, made it run lean

may go to the junkyard later on and grab all said parts and see if there is any differnce, untill then anyone got any ideas

about the brake booster vac leak, ive had that happens it makes a odd but distinct sound so thats not it