Strange Rough idling

**Boise89GT** · 10-18-03, 18:42

I realize the rough idling question has been discussed multiple times, but this is a "could this possible be the cause" question.

We just got done replacing the plugs and wires on the 88 GT with NGK v powers and NGK wires (via sparkplugs.com). They said that they come with an "OE gap of .044." Well now, the car idles really rough, and if revved above ~1500, the RPMs go all the way down and it stalls out. It starts up just fine and idles a little rough but steadily at 750. The thing is, the OIL light has come on and when I pulled the dipstick, it shows up as being very low.

Could either of these be the problem, or did perhaps something else go wrong?

**Dex** · 10-18-03, 19:42

First things first, put more oil in your car, and see what happens. But assuming the plugs are gapped right, and the car seems to run etc, I would check for minor tune up problems, start with the fuel filter, if it were clogged, you could get a rough idle, or have problems keeping the car running, check your distributor for moisture, check your timing, 1 or 2 degrees off the wrong way will make your car miss once in awhile. Try basic maintenance stuff, if that doesn't work, pull codes from the ecu, see if anything shows up. Also, check the connection to your VAF, the electrical plug, once in awhile these like to pop out.

**Thumper** · 10-18-03, 23:00

Have you made any mods to the engine, or had to disconnect any vacuum lines? If all tuning aspects are covered, this would be the next place to look.

**johniebgoode** · 10-18-03, 23:52

Quote:

Originally posted by Boise89GT
We just got done replacing the plugs and wires on the 88 GT with NGK v powers and NGK wires (via sparkplugs.com). They said that they come with an "OE gap of .044." Well now, the car idles really rough. The thing is, the OIL light has come on and when I pulled the dipstick, it shows up as being very low.
Could either of these be the problem, or did perhaps something else go wrong?

~Hey Boise, a couple of questions to ask yourself:
1) How was the car running prior to changing the plugs ?
2) Has your oil been low for awhile ?

~My suggestionswould be:
First as Dex mentioned, get the oil up. For a fresh start, do a change if it's been neglected. Then double-check the plug's gap and also make sure that they're properly tightened. Also, the ignition wires must all be securely connected. This is a good time for replacing the disty cap & rotor, for a complete tune-up.
And next if still having problems, as Thumper stated, any mods may need looked over along with trouble-shooting the basic general PM stuff.

**Boise89GT** · 10-19-03, 2:38

Alright, so I went down to the local Schucks with the intent of buying a gapper so I could make sure that wasn't the problem, they recommended checking the timing as well, but I havent changed the timing and it ran just fine before we did the plugs. While at schucks, we picked up 2 quarts of oil and put them in... it took both until we passed the Low line on the dipstick. (It isn't my car so I'm not sure when the last time the oil changed was

, but I am dragging her down for a change Monday). All we did was change the plugs and wires so I know it wasn't a boost/vac leak, as I've had those before... but it felt similar.

So we left it alone for a while and came back. I checked all the connections twice and they were fine, so it wasn't a connection problem. I decided to go ahead and replace all the plugs one at a time with the old ones... and it worked after we replaced the first one. It was in tight (but not too tight), and the connection was just fine, so it must have been a bad plug. We are going to get the timing checked when we get the oil changed... so we'll see if it was more than just a bad plug. Let us hope it was just the plug, though. Thanks again for the replies.

**Boise89GT** · 10-19-03, 6:46

I was wrong.

Got in the car a few hours after it was "fixed" and the same thing. Returned all original spark plugs and the same thing. I didn't remove or loosen any bolts in the distributor, so could the timing have been thrown off?

Also, could a clogged fuel filter cause this? I mean, the running fine until you step on the gas? I would think the fuel filter thing would cause it to stall even in neutral with no throttle.

And why would any of these just start happening when I replaced the plugs/wires? I am so confused and don't really have the money to get the car towed to a place that can adjust my timing.

**White90MX6** · 10-19-03, 9:22

Check for a leak in your intake pipes, or throttle body boot.

I would say that you have probably knocked off a vacuum line, or your TB boot has split... or something similar. Double check everything, I'm pretty sure that is what it will be.

Tripharn

**Jon** · 10-19-03, 14:07

Quote:

Originally posted by tripharn
Check for a leak in your intake pipes, or throttle body boot.

I would say that you have probably knocked off a vacuum line, or your TB boot has split... or something similar. Double check everything, I'm pretty sure that is what it will be.

Tripharn

on this suggestion.

Be sure to bend the TB boot around a bit to make sure there are no hidden cracks.

Also, make sure you didn't knock the plug off the VAF while you were originally changing spark plugs.

**Methman** · 10-19-03, 15:25

Also your fuel pump may be going bad...it sounds too me like your car has just been neglected....give it a full tune up, So you alredy changed your plugs so thats taken care of., now do your plug wires, distrubtor, cap & rotor, then ignition coil. Then change your oil &oil filter, transmission fluid, fuel filter. Pour some fuel injector cleaner in your tank with your next fill up. Check all vacume hoses for cracks..or better yet replace all the vacume hoses (this is your best bet).
After you do all of that stuff and the car is still having problem then you can rule out general mantanice issues. So now check you CAT to see if mabey its clogged. Behind the Throttle body check to make sure all of the hoses are connected, check your VAF plug, having your VAF checked also wouldn't be a bad idea.
You can get your timming checked its should be at 9-10 degrees BTDC, however, its highly unlikly that your timming belt skipped a tooth or whatever.
It also sounds like it could be a problem with the fuel system, so once you do the tune up with the new fuel filter, get your fuel pump checked/replaced also, doing all of these things should fix the problem hopefuly.

methman

emexix · 10-20-03, 20:10

go into the auto parts store, grab some high end lube concentrate. clean that baby right out. if you got any dirt or grit in the engine while changing the plugs, that could cause a rough idle. this stuff will run through, clean up any deposits, dump them in the bottom of the pan and KEEP THEM THERE. trust me when i say, that shiznit works. and i speak only from experience of putting it in my own 6. just something to keep you tided over until payday, it only costs about $6 at most. may help.

**Boise89GT** · 10-21-03, 16:10

thanks again for all the replies
We took the car to get brakes done (it was down to 20% in the rear), got an oil change and got the timing checked. They said the timing was just fine. It must have been a clogged oil filter or something because she is running just fine now

.