my1999 alero sputters and spits on start up but wont start my 1999 alero has 180,000 + miles and i just resetntly got a cat back exhaust put on the car and now i am having all kinds of problems the car sputters and spits on start up and still wont start all the lifghts are flashing in the dash and rpms are going crazy. but after 10-15 tries it will start like nothing was wrong.
(i was tilold that the PCM might have been zapped when the exhaust was welded on could this be true?) Some body please help!

I doubt the PCM was damaged when the CATBack exhaust was put on. But it is possible the 02 sensors were. Check the rear first and then the front. Also make sure none of the fuel system and evaporative emissions components were damaged at the rear of the vehicle.

Are you getting an SES/CEL light and is it flashing? SES light flashing means the PCM has detected a misfire condition.

no none of the lights are on but the water level light also started to go on and off but there is plently of water in the car and over flow tank.
i just got stuck a home depot 15 min ago (car wont start and now the security light was on) i went inside for 30 min and then came out and car started right up. (if the o2 sensors were damaged wouldn't there be a check engine light on?

The O2's aren't keeping your car from starting. I don't know what the problems is though, sorry.

That's why I asked whether the SES light was on. You may have passlock problem since the SECURITY light was on. If the colant level light is on you may have air in the cooling system and it needs bleeding. Did you ever get your intake manifold gaskets changed if you have the 3.4L?

no, are they suppose to be changed?
Sorry the Service engine soon light is not on. it is really crazy?
that is why i am steering to the PCM, because it controls it all. (but like i said it all started after the welding of the exhaust?

no, are they suppose to be changed?
Sorry the Service engine soon light is not on. it is really crazy?
that is why i am steering to the PCM, because it controls it all. (but like i said it all started after the welding of the exhaust?


The intake manifold gasket has been a known issue on Alero with the 3.4L for years. Most of us had ours replaced either under warranty or at our own cost. Check your engine oil and coolant for possible cross contamination. Also, make sure it is not using excess coolant since the level indicator is acting up.

The PCM is a possibility but I'd check what they could have possibly damaged underneath first. What if they fried the wiring harness to the 02 sensor during the welding. Hard to say what effect that would have on the PCM module especially if 12v heater and the reference voltage from the PCM is shorted out, etc. Look for the obvious first. What if replacing the PCM does not fix the problem?

The best you could hope for at this time is for a DTC error code to show up.

i will see if the intake was changed. now for the water level light every time it goes off i would check it and thier is water there, but the radiator hose to the thermostat is very spongy like air in it, does this mean the water pump is going? or like you said air in the line but how do i get it out(never done this, with this kind of coolant system.) thank you so far. (i have had the car for 2.5 years and none of this has ever happened, this is what i don't get)

i will see if the intake was changed. now for the water level light every time it goes off i would check it and thier is water there, but the radiator hose to the thermostat is very spongy like air in it, does this mean the water pump is going? or like you said air in the line but how do i get it out(never done this, with this kind of coolant system.) thank you so far. (i have had the car for 2.5 years and none of this has ever happened, this is what i don't get)

To bleed out air there is a brass fitting-valve on the heater line at the top of the water pump. Open the valve and air can be bled out. Exercise caution if the engine is warmed up. The line is metal and black and runs in front of the valve cover. Unless it is overheating I don't think it is a water pump.

my1999 alero sputters and spits on start up but wont start my 1999 alero has 180,000 + miles and i just resetntly got a cat back exhaust put on the car and now i am having all kinds of problems the car sputters and spits on start up and still wont start all the lifghts are flashing in the dash and rpms are going crazy. but after 10-15 tries it will start like nothing was wrong.
(i was tilold that the PCM might have been zapped when the exhaust was welded on could this be true?) Some body please help!


same thing happened to me rpms went crazy spedometer went crazy...basically my whole dash display go check out your battery aleternator and starter:smooch:

Welcome to AF alerofreak , and thanks for the comments.

Please, from now on look at the dates before posting in outdated threads.
No need to bring up anything older then 3 months, Thankx.

this is Closed!