1999 Lumina LTZ Stalling at will

[mikey1157]

I just purchased a 1999 Lumina LTZ with 145K miles. The car was maintained by fleet mechanics over the years, but has set for about 7 Mo. It drove fine for the first 100 miles and then it began to buck and stall at any RPM range. It re-starts easily, but the engine will break up at 4000 RPM. Once the rough running stops it doesn't break up at 4K, and will not stall. The Car has great performance when not in one of its hissy fit periods. Does anyone have an idea what I should look for. Thanks.

[EAGLESFAN]

I have a very similar problem...it seems to be quite random...most of the time she runs great...but sometimes it's like she's on her period. I haven't found a solution yet. Run your codes, what do you get?

[mikey1157]

Ran codes, nothing to report. I wonder if an "Idle Re-Learn" would help?

[mikey1157]

Originally Posted by mikey1157

Ran codes, nothing to report. I wonder if an "Idle Re-Learn" would help?

I finally got a code P0103, it's a temp. code but it's a code none the less

[maxwedge]

This code refers to a high input from the maf, either dirty or bad or has a bad connection. see this link http://service.gm.com/gmspo/mode6/pd...c38K_CFHWE.pdf.

[eraticstatic]

I've had my Lumina for the past 7000 miles of 112k. About 4000 miles ago, it started a little dip or hesitation in rpm's at idle. It always came back and ran fine. Yesterday, after driving for 15 miles, and sat at an idle, it severely dropped in rpm catching my attention. Then again about 3 more times. I got moving again and it died on me while rolling through an uncontrolled intersection. While still moving, shifting to neutral and restarted. The rest of the commute it would hesitate hard after a stop at about 15 to 20 mph.

Then today, again after driving 15 miles, it died on me around a corner. I recovered. From my destination back home it died another 15 times in the course of 20 miles. From a stop, 10-20 mph, freeway, didn't matter. I made it home and start checking forums and everything I saw pertained to other years but had to do with fuel pump and crankshaft sensor. I got a call back from a friend who had similar issues and his fix was an ignition module. I then took it to Schucks (~15 miles) it died once. I decided to shift out of OD into drive for higher rpms giving the ecm a higher buffer to recover from whatever the cause was. It still hesitated from stops as well as acceleration. I saw a jump in the tach without any different pedal input, these rpm fluctuations affected shifting (differing pressures causing in and out of the gears hard), and a lurching of the entire vehicle seemingly at random.

The guys at Schucks gave me the code scanner and came up with a mass air flow sensor discrpancy. So I went in and asked how much and he said $150. Well, I took out my old one and looked at the new one and saw no differances. The muli-meter showed no differences between the two checking ohms and continuity between the 3 posts of each. So after discussing it with the counter guy (who was ASE Certified, which added to his opinion) and considering what I had read and what the computer read, I decided to buy the sensor. After clearing the ecm, I ran the car in the parking lot in park at variouse rpm's with A/C on as a load for about 8 minutes. I kept the scanner on and scanning for codes and came up with none. The drive back to my house was uneventful.

I would also like to add that another symptom is when starting, the need to crank about half a second longer then what would seem adequate. If I didn't, would lug for about half a second and die.

Hope this helps.

[richtazz]

You can easily eliminate the MAF by simply unplugging it. The car will have to adjust for a short period, and the CEL will come on, but the car will no longer stall with the MAF unplugged if it is the cause. If it continues to stall with the MAF unplugged, and if the tach suddenly drops to zero just prior to the stalling, the crank position sensor or the wiring between it and the ICM are probably the cause.