Hello everyone,

I have been fortunate enough for the last several months to not have to post any questions about my '93 coupe (142,000 miles).

A while back, it seemed everything went wrong on it all at once (transmission rebuild, new tires, cooling fans, u-joints, serp. belt, etc...) all within a month of each other. Since then, things have been pretty calm. Aside from an overheating problem, which was remedied by installing a new thermostat, radiator cap, coolant system flush, and temp sensor, I haven't had to complain much.

However, for the last few weeks something has been acting up occasionaly.....

One afternoon, I went to leave work for the day, started the car, and the idle was very rough, and it kept wanting to die. There was a strong smell of exhaust coming from the engine compartment, and if I gave it some gas, the roughness went away and seemed to respond normally. But as soon as I let off the gas, it would choke down and would die if I didn't give it gas. Well after about 10 minutes of sitting there playing with the gas pedal, the idle was still rough, but it would continue running on it's own. So I left and drove home, and going down the road if I punched the gas, it responded perfectly, but when I stopped at a light, the idle was still a little rough.

Parked it for the night, and fire it up the next morning with no problems at all. It ran fine for about a week or so, and then it did the same thing again, only without the strong exhaust smell. It has done this 3 or 4 times over the last few weeks, but seems to just do it once, and then go away for 5 or 6 days. Tonight it did it and I had my headlights on, and when it started to choke out and want to die, my headlights would dim, and as I hit the gas to keep it alive, the lights would go bright again.

Where should I start?

-Plugs and wires were changed about 2 years ago..
-injectors have never been changed since I've had it (91k miles-142000 currently)

Thanks.

Adam

 

Load Test Your Alternator
Check Fuel Filters
Check Fuel Pump
GET INJECTORS TESTED OR CLEANED
Plugs/wires
Throttle Body Cleaning / Sensor
How Old Is Your Opti? That Can Cause All Types Of Issues.

 

My 93 was doing almost the exact same thing. Did all the checks that I could do and what was suggested on here. Water pump went out, so since I was doing that, checked my opti. It was bad so replaced it just this Tuesday. My car runs better than it ever has since owning it. May not be your problem, but surely was in my case.

 

Your alternator is probably ok. Very low engine rpm will cause the alternator to turn too slow to generate enough current to supply your electrical needs and the battery then supplies the current and your lights will dim. If you can pull a plug wire and bring a grounded wire close to the plug wire and start the engine when it won't run well, you can tell if you have a normal spark and if the optispark is ok. You should see a spark easily 1/2 inch long.

 

Don't rule out the ECU.

I had a miss that I threw far too many parts at without success until I threw an ECU at it.

 

Checking the coil resistance of the injectors hot and cold is a very easy and quick diagnostic test to help rule out things.

 

well today after lunch, it acted up again, and I sat there for like 15 minutes and it still wouldn't warm up and hold an idle on it's own. So I decided I needed to bring it into my shop. I had to do some fancy driving to get it the 13 miles down a few roads and a lot of stop lights. Shifting into neutral when approaching a light, braking with my left foot, keeping a little gas going with my right. But alas, I made it to the shop.

They scanned it and said that the opti was throwing a code, but by then, it stopped acting up, and they couldn't duplicate the problem. They were going to leave it hooked up to the computer overnight to see if they could pinpoint anything else or at least verify that the opti is bad.

If so, am I ok to just get a replacement from autozone or somewhere similar for $150 and have them put it in? I've seen people talk over the last few years on the forum about expecting to pay over $1000 to replace the opti? is it really that much labor? Should I or can I get the newer opti that is redesigned from my 93's model that is less prone to water damage?

I've had the car for a little over 3 years, and it has 142k miles, and I haven't replaced the water pump, and don't have any records of it being done before I got it, so I should probably change out the water pump while they're at it just to be safe right?

I guess I'll find out tomorrow what they say at the shop....

Thanks for your input.

Adam

 

This won't make much sense but it could be as simple as a temp sending unit. Thats what mine was with similar symtoms.
It was indicating it was cold and sending f to much fuel .
$15 part.$40 for the diagnostics.
Good luck