hiccups and hesitation, backfiring in airbox

[idontknowhow]

I've replaced both fuel pumps ran the car on premium fuel with injector cleaner, cleaned the idle stabilizer valve, cleaned the throttle body, replaced spark plugs and wires, new air filter, new fuel pump fuse and relay. It has been sitting in my neighbor's yard 4 four years and he said it ran fine back then, after all the replacements i finally got the car to run, it runs great when you first start it, but after it warms up, the idle changes and goes up and down a lot, then when you push the gas it hesitates and the RPMs go down, after pumping the gas i can get the rpms up enough to drive it, it will backfire in the airbox and now there is oil showing up in the airbox and it smells really bad of gas. I have checked all of the vaccume tubes, there are no leaks and no blocks. I am completely stumped, any Ideas?

[bigLdubz]

i have the same problem trying to fix it now let me know if u find anything out

[roscoe crawford]

what year and have you checked fuel pressure? what type of fuel system cis cis-e also check throttle plate

[pete1.8t]

Hey I've got something similar happening. My car hesitates real bad when the throttle pedal is pushed then all of a sudden it just takes off. It also back fires through me intake when the throttle is pressed down. I am thinking it has something to do with my combi valve (EGR valve) or maybe the combi valve controller. Maybe it is sticking open and all intake air is going straight out the exhaust.
Could you please post what your findings are. I am having a heck of time trying to finding anything on this issue.

[armymech666]

my girlfriends car was doing this and I replaced the knock sensor and fixed some vacuum leaks. the knock sensor was crumbling apart so I believe that was the main cause but I can't say for sure because that was a little while ago and I have a horrible memory.

[VR6witHRE]

any one figure this one out beside the knock sensor?

[bigLdubz]

my deal was my cis distributor .... got a rebuilt from german auto parts mad dough

[VR6 GLX Man]

I have a 92 gli, do you guys have these symtoms right when the check engine light comes on, my problems occur whenver the light comes on which is after I drive off. Sometimes it doesent do it for a lot of miles then other times it startes after I start driving off from a cold start.

[jsvr6nsd]

Have any of you guys check out your intake valves on your heads? If you car has higher mileage it is possible for valve springs to wear out and cause leaks which would cause backfire in the intake and the smell of gas also.

[team~bunny]

If via check fuel pressure, then the fuel accumulater.