Engine surging at idle, rpms are dropping. Please Help

So i have a 2008 aveo5, 44800 miles, that had been a great car until recently. The car surges at idle and tries to die. I've replace the serpentine belt, the timing belt and the idler & pulley, the throttle body, spark plugs and wires, the air filter. When i stick my head near the engine I hear a suction sound and smell exhaust. Could an exhaust leak cause the rough idle issue? Anybody else have/had this problem? Any help would be awesome.
I have an extended warrenty until 72000, but my local goodwrench shops have been no help so far. Maybe if i can figure out the issue i can tell them what to fix...
Thanks in advance,
TJBEAN216

high idle sounds like a vacum leak, not sure about the rest

suction sound and smell of exhaust with rough idle sounds like a leak in the egr system.

Thanks for the replies. So no more suction sound, but I still smell exhaust and have that rough idle. It seems way worse when the a/c or heater is on in the car. should have them check the egr system still?

Also would it throw a code? Because each time I go into my dealership I'm told that no codes are showing up. Thanks

The check engine light would be on if there were any codes usually. Who did the timing belt btw?

could still be egr, could also be a cracked exhaust manifold..

Alright I'll have to tell the mechanic to look at those two things. Are there ways i can check at home easily? I like to do my own work, but i don't want them to void my warranty. @thehunterooo my local hometown shop did it for $80 plus parts. I think i replaced all of the components for about $220.

things you can try before paying..

cleaning the throttle body yourself, they get gummed up. could be the surging idle, but not the exhaust smell.

check egr actuator for leaks, it will suck in most likely, mist it with starting fluid and see if it raises rpm (do this ONLY on the intake side, not exhaust)

mist the coil pack and wires with water.

check spark plugs.

thats about 30-40 minutes of work to eliminate a bunch if potential issues.

Damn that is a good deal, did you noticed any changes with the car at all after the timing belt was changed?

No it was idling rough before, and that's why I changed the belt. I thought maybe it jumped a tooth or the components were bad. Unfortunately no luck, but at least I got a new belt out of it.

So the guys at Goodwrench think my spark plugs are missing a gasket, which caused the wires to fault. 250 to fix it, which is asinine, but the fiance says to have them fix it so if anything else is wrong it doesn't fall back on us. Hopefully it's fixed. Thanks for all your help, i'll update you later.

I would take it to a local shop and avoid any dealership or other mainstream repair centers, I did not know there was such a gasket like that (valve cover gasket?)

btw, did you ever take it back to the shop that did your timing belt? I would have had them look at it, if it is the valve cover gasket (makes no sense to me though) then they should do it for a lot less.

Yeah they looked at it. They couldn't find anything. Timing belt is lined up, and the valve cover gasket had been replaced. It's a silver o-ring that goes at the bottom of the spark plugs that was missing. When your a/c is on does your steering wheel shake/vibrate a lot at a complete stop?

Ahh that is something I know nothing about myself :(

My steering wheel does not shake very much when the A/C is on full blast, there is vibration but nothing out of the normal. Does it shake a lot when it is off or when it is just on?

Both, and it doesn't matter if it is the a/c or heater is on the wheel vibrates enough that I can hear it. It's worse when air is blowing

If you can have it checked out for free, might as well (Shaking steering wheel=bad motor mounts usually, may be something else though).

is the wheel shaking while moving or sitting still?

the crush washer on the bottom of spark plugs is on almost every spark plug, how is your car missing them?

i do not see how that would cause the problem, i suggest first misting the wires and coil pack to see if they re shorting out. then figure out if the proble, is actually the valve cover gasket (oil on plug wires etc)..

The wheel shakes while sitting still. I'm not sure how the plugs didn't have the crush washer, but sure enough they were. Missing the washer caused the plugs & wires to go bad, luckily the coil pack was still good. The car doesn't want to die now, the only thing i notice is the shaking steering wheel. We've owned the car two years and it has only been recently that the wheel shakes.

i got a 2005, swap engine with new timing belt, plugs, wires,swap coils and same rough idle, runs great but idle bad.
any ideas?

Honestl it beats the hell out of me. I'm starting to wonder if it could be a bad timing belt tensioner

Not timing, sorry I meant serpentine

sounds like the same problem as I have... Let me know if you figure it out!

So boss lady traded it in today. Bought an sx4 so I'll be around. Good luck on that issue markram