Just bought a 99 S70 sedan, It has about 195k miles on it. Drove fine all day, No issues. Went into walmart, Got some oil and new headlight bulbs.. Installed the lights and put the oil in.... Tried to start, and it wouldn't... and when it finally did, I didn't have any throttle, And it kept surging. When it would idle, It was almost like it was missing.... I could give it throttle, But it would barely go above 2k RPMs.

If I turn it off, and then turn it back on.. First try, It stalls... Start it up again, It revs (ON IT'S OWN) to about 3k RPMs.. Then drops down, Sometimes it'll rough idle like it's missing, Other time it just sits there and surges up and down... I push the pedal, and it'll rev a tiny bit then go back to surging.

What's the problem?

I don't think my CEL even works... Because even when I turn the car on, It doesn't come on.

Well, Heres where it gets real weird.... I tried starting it today after it sat all night long... And it started up just fine! Idled fine, Revved fine and everything! So I let it run for abit... Came back outside.... Yep, Sure enough... idling rough, Surging, and not revving past 3k RPMs.

So I checked for air leaks, It had a few... Fixed those, Cleaned the sensor in the air box and in the air intake hose, Unhooked the battery for a while.... (This was after it sat for a while again) and it started up just fine again, revved fine, idled fine.... then I guess once it "warmed up" it started idling really rough and not revving like it should.