97 Tercel: Been sitting, runs rough, ODD PROBLEM..read on...

Probably a combination of resetting the ECU, and, did you put any GAS in it while you were out with it?

My first 'guess' was old gas. My second guess was that one of the coil packs was shot, but looking at the ECU wouldn't fix that.

When the ECU throws a code and the MIL comes on, the car goes into 'limp' mode. It will run, but not real efficiently (how about a 10 MPG difference on my '95!!). It may have been in limp mode, and when you reset the ECU it reset and is running properly.

Drive it for a few days and see what happens. Then post here and I'll come and get it! (missing my '95..)

Hooking a car up to a code scanner will not make a difference in how the engine runs.

The car will have to be checked out to properly diagnose the problem.

Bull! They didn't tell you in class about the "Never do it in front of the Mechanic!" circuit in the OBD-II connector? Plug in a code scanner, and no matter what the problem was it'll clear right up...

;-P

This used to be much harder for the car makers to pull off reliably and undetected before the advent of computers and OBD - like the flaky ignition modules that would only fail while off-roading 20 miles from civilization, they had to rely on an old-fashioned "Critical Need Sensor" (made famous by Murphy Industries) to decide when to fail.

But thanks to modern electronics our cars and trucks can frustrate us a whole lot better and more reliably than ever before.

"When they're good they're very very good, but when they're bad..."

-->--

PS: Okay, I'll let go of your leg now. Sheesh.

LOL! I am very familiar with that circuit. It seems like only a small percentage of the cars I checked out actually exhibited the condition the customer was complaining about on the first look. I'd tell customers that it is like going to the dentist with a toothache that miraculously disappears as soon as you're in the dentist's chair.

Unfortunately, even with the advent of OBD II, someone with a clue has to look at the car in order to figure out what is going on.

OK, let's call it limp mode. So why might this have naturally occorred after a couple months sitting? And why/how was it cleared at A-Zone. No gas was added. Just the problem and a trip to A-Zone and everything was good after that. That was the first time. Now it's sitting again and apparently behaving the same way again. I'm trying to find out if this is typical and if I repeat the "fix" and drive it regularly if anyone forsees any problem. The guy that did it before never had a single problem and got the 30mpg after his trip to A-Zone that I described. Thanks.

KL

Some people drive like corpses and their cars get clogged arteries. Letting a car sit will cause the same thing. Do you drive like a corpse?

Actually, I would not call it "limp mode" because that is a different condition.

Cars run poorly after sitting for a while for several reasons. Animals can chew wires, debris can accumulate in the air filter and intake plenum, gasoline forms varnish-like deposits on injectors, and discharged batteries become sulfated.

I think that it would be worth investing some time in changing the spark plugs, air filter, coolant, and oil and investing in some Techron fuel injector cleaner. Be sure to follow the fuel injector cleaner directions carefully so it doesn't eat fuel lines.

I have no idea why the car cleared up after visiting A-Zone because hooking up a scan tool has nothing to do with how it runs, any more than checking your blood pressure will lower your blood pressure, or taking an EKG will clear up a heart problem.

Any possibility it could be some crap in the gas tank - seperates while sitting then gets mixed with fuel due to the movement of the car.

Possible but not very likely.

So the mass opinion seems to be that it's an age/lack of use/sitting thing...NOT some "nature of the beast" ECU/sercurity system issue that anyone else has ever experienced? And yes, one friend thought it was some kind of "disable" for the security system after sitting or the battery going dead or something. So, apparently the trip to AZone did and could have done nothing. Damn. Now I'm not sure what I'm getting into. Otherwise the car is tip-top except for the M/T which has to be replaced (main bearings). Any thoughts on this or these trannys in general? Thanks.

KL

A problem with the security system is more likely to cause a no-start condition, not a poorly running engine.

As I mentioned, scanning codes does nothing to the ECU.

Start with the stuff I mentioned before. Good luck!

Ok, I have more clarification. Not much help, but info nonetheless. So, like I said the car has been sitting for approx 6 months and runs rough (like running on 3 cyls or worse) upon starting. Ok, throw out the Autozone bit if you wish:

Apparently at any given time you can go out and start it and it will purr like a kitten for a minute or three and THEN start acting up and running rough. The pattern varies. All filters and ignition parts are allegedly no more than 20k old. Just some more nuggets if that means anything to anyone. Thx.

KL

Oh, and most importantly, did I mention that it's a BlackHawk? Heh-Heh! There ya go. Now you know everything :-)

I think you will need to have a competent technician look at the car to determine what is causing the problem. Things to check are the ignition system because Toyotas sometimes do not run well on aftermarket ignition parts; fuel delivery (check fuel pressure and volume to see if there is a problem with the fuel pressure regulator, fuel filter, or fuel pump); idle air control valve; MAF sensor; manifold vacuum; and leaks or cracks in the intake snorkel between the MAF sensor and throttle body.

I don't have my factory manual handy (mine's a '96) to check on how often the fuel filter is supposed to be done. However, I did just do mine last night, and if one believes the information on the side of the box that the new one came in, Purolator seems to think it should be done every 12K.

How interesting. I know that when I pulled the old one last night, when I looked into the top, the filter element was a nice shade of brown, as compared to the white of the new one. (The old one was in there *much* longer than 12,000.)

Add to this my previous experience with my Mazda 323; driving home one day after work, when the engine died suddenly. Ended up being assisted by a person at a nearby store (automotive related somehow, I can't remember exactly); while trying to troubleshoot the problem, he checked the fuel coming out of the filter, didn't like what he saw, and chewed my butt for not having changed the filter.

While I've got your attention, just how difficult is it supposed to be to wrench in the bottom fitting on the filter? Both times that I've done it with this car, it's been extremely tight all the way, both coming out and going back in on the new one. The top bolt had no such problem.

That's pretty much a given. :-)

I was worried that I might have been crossthreading the blasted thing.

That bit of wisdom I *must* keep in mind.

Yeah, I think I should come and take it off your hands. Have a check ready for $125 when I get there... ;)