My Mk4 Astra Sri 2.2 16v has a lumpy idle when slightly warmed up.It ticks over at just over 600rpm but can feel it through the seat,and when the lights are on,can see them flickering.When driving it at lower revs,you can also feel it very faintly after starting the car from cold,but when its fully warmed up,its fine when driving,just not on idle.Dosnt cut out either.
Now ive done a search on google which came back with EGR and CTS being the main suspects.Now,my brother has a perfect running 2.2 so tried his EGR,but was still the same.I also tried his CTS,but again,still the same.I then snapped the CTS in the housing so had to go get a new 1 anyway,but still the same so can deffo rule that out.
What would be the next thing to try??As said i have access to a perfect running 2.2 so can try other things(within reason) to rule them out and try find the problem.
Its not annoying me and dosnt affect the over-all drive of the car,but i would still like to get to the bottom of it.
Pedal test dosnt work either.EML light isnt on,but does work
Also when i start it from cold,the revs sit up at 1200rpm(normal when cold)but it sounded like it had a missfire possibly.Heard it through the exhaust slightly.Also when its cold,if i drive along in say 2nd/3rd at 1500rpm,it feels like the car is surging back and forth but by the time i get to work 1.5mile away,it dosnt surge back and forth.Just lumpy once parked up.
Today ive tried the coilpack and inlet temp sensor thing in the intake pipe but still no different.Plugs look fine also,only 3 months old.Bosch triple electrode if that makes a difference.
As said,on WOT the car pulls like it should and drives spot on.Had a go against my brothers Astra 2.2 to see if the performance was down and there was nothing in it between the 2 cars.Dosnt use any oil and isnt smokey.
A friend has Op-Com,is it worth putting that on it to check for codes to rule stuff out.