96 Lumina: Random Multiple Cylinder Misfire

Thank you in advance for any help. I have a 1996 Chevy Lumina, 4 door sedan, 3.1L.

The past couple weeks, the car has had trouble starting when it has not been run within the past 5 hours. Especially in the mornings when it is cold outside (temperatures below 15 fareheit). The car starts fine after that for the rest of the day and drives fine with plenty of acceleration.

5 days ago, when started, the engine sputtered upon ignition for about 30 seconds. The check engine light came on. Being close to an auto store, I took it immediately to see what the code was. On the short 5minute drive, the car drove fine and the engine light turned off, but they were able to pull the code for Random Multiple Cylinder Misfire). This happened again yesterday, but the check engine light never turned on.

Another problem is that there is a very slow coolant leak for about a month. There has only been a little puddle once, no more than a few table tablespoons. Otherwise, there is never any signs of a leak. The low level warning light never goes on even though it is very low in the resevoir. I stay on top of trying to keep it filled. I smell the antifreeze when the heat is on.

Please help. I do not have hardly any money and would like to make sure that I am fixing the right things. After reading other peoples forums, I do not know any trustworthy proffessionals that I can take this to and not have to worry about being mislead. If I am able to fix it myself, I will.

Thank you

I hate the random misfire...difficult to figure out.

Since it only happens on start and in extreme cold, it could be nothing more than it's choking a few ice crystals through an injector or two, because some bad fuel froze up in the rail overnight. Or it could be cold fouled plugs. Or coolant getting into a cylinder overnight (hope not)...or any of a couple dozen other things....

Since you mentioned the mystery coolant leak, I'd wanna rule that out as being connected to the other problem right away...but it won't be convenient. You'd almost have to let it sit and get real cold, and if it's chugging when you start it, shut it off IMMEDIATELY and pull the spark plugs and see what you see. Oil? Fuel? Coolant? Nothing?

Of course if they are really old, change them anyway....you didn't say how many miles you have or what kind of maintenance history....the factory platinums will run 100,000+ miles, but pretty worn by then.

I have a '97, and it used to occasionally misfire like it had a dead hole on start-up...very rarely, and it never went on long enough to set the CEL, but now that you have me thinking about it, hasn't happened since I put the new plugs in...at 115,000 miles....

Anyway, it sounds like you very possibly have a heater core leaking at least...if you can get under the car look for the core drain (where the A/C water sweats outta the box in summer), see if it has a drop of coolant hanging in it....sometimes with a core leak, it leaks into the box, doesn't build up enough to show much leakage where you park, because it sloshes out through the drain when you're driving. Check under the passenger's floor mat for suspicious wetness too. Sometimes they'll leak onto the floor, although you'll usually smell it real bad.