I recently filled up my car with a tankfull of Mobil's "special" grade (89 octane) gasoline. Since I filled up, the Classic is running like shit, the idle is constantly stuck around 1500rpm and won't go down, and my throttle response sucks-which is even worse because I just installed a Place Racing CAI, and was becoming quite fond of the extra power http://laf.cioe.com/~benbobbo/NonCGI/frown.gif I figured my fuel filter got "nuked" by a bad tank of gas, so i went out got a new filter and installed it. I then drove it around for a few minutes like I normally would, and stopped. The same thing-crappy idle, poor throttle response. Do you guys think a)It's the fact that I had been running 92 octane in it for awhile before I was "stuck" and filled up with Special(they were out of Premium and I was in the middle of nowhere)Or b) My AIV valve is screwed up because I had to throw a breather on it when I installed the CAI. Someone on SE-R.net had suggested in one of their articles that when the AIV goes bad, the idle suffers. It's pretty much been making the same noise it always has, and the car was running great until I put this gas in my tank. I've since gone out and got some 93 octane +octane boost to try and "flush' out the system. Any other suggestions???

Since I advanced the timing to 17 degrees my idle has been pretty high as well, 1200~1300 rpm. It doesn't seem to have had an effect on the car's performance or smoothness. Recently my car was running poorly, so I changed the oil to Mobil 1 full synthetic. The old stuff (dyno) looked really bad when it poored out of the engine. If you haven't changed your oil recently and are not useing synthetic, do it. My engine has never run this smooth, and it only has 39,000 miles on it.

Though it seems unrelated, you could try unplugging the hose between the EGR valve and BPT valve (the two bronze-colored "mushrooms"). I was having some low-end drivability issues on my '92, and that fixed it.

Clogged/broken EGRs are common on classics from what I gather.

The first thing I did, besides changing the Fuel filter was clean out the BPT and EGR the best i could. I have a feeling the drivability was from the "bottom of the tank" fuel that I got at that gas station http://laf.cioe.com/~benbobbo/NonCGI/frown.gif Nothing like filling your fuel tank with sediment....

The first thing I did, besides changing the Fuel filter was clean out the BPT and EGR the best i could. I have a feeling the drivability was from the "bottom of the tank" fuel that I got at that gas station http://laf.cioe.com/~benbobbo/NonCGI/frown.gif Nothing like filling your fuel tank with sediment....BTW, I have been running Mobil 1 in the car since I bought it.

Update-now that I've run a tank full of 89 octane + octane boost through my car(104 Octane boost, BTW), the idle seems to go up to 1500 RPM's then goes down to 1200RPM's and, occasionally, it actually goes down to 750-800rpm's every so often. Who knows? Maybe this thing will straighten itself out(I hope!). The driveability has definitely improved somewhat, so at least that's good http://laf.cioe.com/~benbobbo/NonCGI/smile.gif

<font face="Verdana, Arial" size="2">Originally posted by Chris:
Update-now that I've run a tank full of 89 octane + octane boost through my car(104 Octane boost, BTW), the idle seems to go up to 1500 RPM's then goes down to 1200RPM's and, occasionally, it actually goes down to 750-800rpm's every so often. Who knows? Maybe this thing will straighten itself out(I hope!). The driveability has definitely improved somewhat, so at least that's good http://laf.cioe.com/~benbobbo/NonCGI/smile.gif</font>

cleaner your TB lately??? Sometimes this causes the idle to go funky. it did on my car, then after a couple days it worked itself out.

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Ryan Walsh, 1997 200sx SE-R w/ ES mounts, JWT s4's, AEBS 4-1, PR CAI, Greddy cat-back, Sportlines/AGX's, Bridgestone re730's, Stillen GTR grill

Actually ryan, that was the first thing I did when I put the CAI on....Do you think I should get the EGR replaced(the car has 108k on it)? I can't think of what else it could be(except for the MAF or TPS, but I'd rather not fuck with those).

Make sure your plugs aren't fouling....

Hmmm....I don't think it's the plugs, they're brand-new NGK Paltinums w/ less than 10k on them.

hi chris check to make sure you put the maf straight up so you can read it. mine was side ways and made the car run crappy. also try doing your own diagnosis with the ecu, it's easy an quick.

hey redman
"try doing your own diagnosis with the ecu, it's easy an quick"
please explain how this is done
TIA

So, having the MAF "straight up"(whatever that means) will cure my problem? It really doesn't matter, because it looks like I'll be trading in the car at the end of this week, the end of next....I need a car that I don't have to fuck with every day....