on my 2.8 TBI S10 i've noticed its running a bit rich. it used to stink bad of gas and got horrible gas mileage. i did a full tune with all new plugs, wires, distributor cap and rotor, coil, fuel pump,..fitler,..etc....the whole 9 it runs a million times better and gets better gas mileage but still smells a little gassy out the exhaust and i checked the plugs and they were a bit black. the computer does pull a code every here and there for a EGR but i dont know if that is what is causing the problem or if its someting else. i also noticed it runs alot smoother on 93 octain. when i put in 87 it sounds allmost like its missing at idle but its really smooth with 93 which i dont see why that would be. also im looking to get a set of underdrive pullys. im wonder what brand you found the best and if there worth it.

 

What year is the s-10?

I would assume that you have a vacuum EGR valve. They retail for about 40 bucks so I would think that replacing it couldn't hurt (it's probably gummed up). Usually (if the vaccum lines are intact) the EGR valve is at fault.

 

Egr on s10's is not to expensive, go for it. Just need a 10mm wrench and some patience.

Gas smell, try checking the charcole canister too.

Pullys, aspracing.com I feel is the best for the bux. I have the dual set on mine from jetchip, I refuse to deal with them again. Hypertech makes them, and I think marchpullys does too.

 

Tempest, did you replace the O2 sensor? A bad O2 sensor will usually give off a false 'lean' reading to your computer, causing it to dump more gas in to compensate and actually make you run rich. And it usually DOESN'T throw a code when it starts reading incorrectly...only throws a code when it stops working, which by then, your gas mileage should be horrific. What kind of spark plugs are you running? I strongly recommend AGAINST platinum plugs. I put brand new Bosch platinums in. Ran great for about 5 days... It's only been about 2 weeks and the plugs are fouled already..car runs like holy hell. Doesn't want to idle, runs rough, misses occasionally. I'm putting Rapidfires in when my new plugwires come in. Also, check your timing. If it runs bad on crap gas but runs good on higher octane, that sounds like your timing is a tad too advanced...make sure it's at 10 degrees...

 

My 93 s10 is to be timed at 0, not 10, wont even start at 10.

Nixon is right on the 02 sensor also. Try that. Its about a 20 bux fix. Need a 3/4 in wrench I belive. Unless you replace sensor day in and day out, the 02 sensor socket is a rip off, and sometimes "strips" the sensor when trying to take it out.

 

i havent checked out the O2 not sure if its ok or not, the truck runs pretty well it doesnt run shaky or get horrible gas milage. but its not that great. i run just good ol' 1$ AC/delco plugs i've never had a problem with them in all the cars i've used them in. a few of my freinds said just dont worry about the EGR as all it does is just pump air into the exhaust for emmissions and does nothing for the drive quality but i dont know.

 

EGR does affect the drivability

 

Yeah don't listen to them, you wouldn't think the EGR would affect how it drives that much but it really does. When they go out the car acts reaaally funny.. Hey Dale...random question..are the open-loop and closed loop operations dealing with the EGR valve? That would be my guess but I dont know for sure..I know the car runs open loop on a cold engine until the O2 sensor has heated up enough to work properly and a few other things like coolant temp...then it switches to closed loop...