2003 Sunfire Stalls once in a while

MrWilHale

Hey all. My 2003 Sunfire 2.2 ecotec automatic has 196000 miles on it and hovers right around 600 rpm after warm up. Most of the time that feels too low and it will even dip into the high 500s when stopped in drive after running for a bit. I have replaced the Plugs (there were almost no electrodes on the old ones when I bought it). The Idle Air Control Valve, Fuel Pressure Regulator (Carbon stuck) and the Fuel filter (which was pretty restricted) have all been replaced by me. I cleaned the Mass Airflow. Checked for Vacuum leaks and have run Fuel Injector Cleaner through it. I have no codes on my ODBII. I do have a motor mount that looks like it is going (explains why it feels a little rough at idle). As I said, only happens once in a while and almost always when it is warming up from 165 to 195 and I am stopped at that time. Any suggestions, no matter how odd are welcome

imidazol97

I don't see anything that you've not played with. When you replaced the plugs, did you replace them with the correct recommended AC Delco plug.

I haven't looked, but does yours still have high voltage spark plug wires or is it the newer system with coils on the plugs and low voltage wires? If high voltage, I'd replace with AC Delco replacements.

The cleaning of the mass air flow sensor can be done with a spray cleaner.

You didn't mention cleaning the air intake where the butterfly valve is. If anyone tells you that can get coked up, the differences in how the butterfly valve seals around the sludge as it closes could cause errors in the fuel mixture adjustments by the computer as it closes due to differences from one time to another. On some earlier cars that car could get caked with oil from crankcase fumes after the car is turned off. I do not know if that's needed on the 2.2. I have experience with 3800s in leSabres for lots of years.

The idle speed is computer controlled. More than likely you're seeing variation in the tachometer readout.

MrWilHale

Thanks for that. I did hit the Intake / Butterfly area with some C and C as i was cleaning the Fuel pressure regulator. Delco Plugs, Thanks for the tip on the wires. It is a coil pack system. Going to see if I can get an ignition analysis tool and see how all of that looks. Might also do a compression test. On a side note, it did it again yesterday as I slowed from 35 to make a right turn at about 5 mph. tried to stall as I began to accelerate. Still right within that temp range. Experienced a hard start later in the day too.

imidazol97

On the 3800's, the protector over the end of the throttle body had to come out and a wooden stick and cloth used with a cleaner, gas, spray, etc., to physically remove the soot gummed with oil vapors that deposited around the throttle body. Eventually some would get enough gunk there that when the engine cooled, the clearance changed and the throttle body was rubbing on the gunk to first open. Gave the feeling the throttle was stuck closed and resisting being opened.

I've not had problems with the 2.2 in my 08 Cobalt.

Had this engine been scanned at a box store just to see and record what codes? Then go home and research them on the internet as to what they might be a symptom of?

And since you seem open to doing testing, have you tested the fuel pressure. Some box stores have a loaner that you can use. I wondered if you might have used one to determine the FPR was not working right.

But my thinking is that at 135 and increasing the fuel richness is being tapered down by the computer based on input from the sensors. You might be getting too lean a mixture that doesn't support the idle while decelerating.

thecardoc3

Will your scan tool show data like long term and short term fuel trims, plus IAC counts?

imidazol97

I was hoping cardoc3 would have suggestions.

You really need to get data about what's happening. Otherwise you can keep replacing parts and guessing.

I decided to search for the problem not by Sunfire or Pontiac, but by searching for 2.2.
I found this fairly similar threat on another site. There are several who have had the gunk in the butterfly valve area changing the airflow by friction on the butterfly making it not quite close or other. Occasionally someone makes a wrong assumption in the various posts here, but I'd suggest cleaning the intake with a cleaner and cloth on a wood piece or something not metal.

Hint: don't use a toothbrush like I did on my leSabre. It's not metal, but the bristles started falling out due to the solvent in the cleaner!

A longer post by vizard talks about relearning the computer after the cleaning and refreshing the seals...


https://www.cargurus.com/Cars/Discussion-t1716_ds471635

I found your post interesting because I have a 2.2 08 Cobalt with the same engine, I believe. Mine has 130K miles.

Vizard has a later post reminding that you can use a cleaner solvent sprayed on the seals and connections with engine running to see if it sucks in some combustible solvent and changes the idle for a second.

Good luck! Please report back if anything works. Otherwise, you need to get the data about the mixture which cardoc3 suggested.

MrWilHale

Thanks Guys. Will be reporting back when I get a chance to run a few tests. I use the Torque App on my phone and a Bluetooth ODBii Reader for DIAG. I am a Trained and Certified Mechanic (Or I was 20+ years ago). I did use the C and C Cleaner to try to detect vacuum leaks, none were indicated

iboughtaproblem

I just bought a 2005 Pontiac sun fire,189000 klms, and it was subjected, that it may stall after driving 20-25?-34 miles which it did, because of a faulty fuel pump install,?well after driving for as said, the car stalled, again and again waited 10 to 15 mins to let the thinking fuel pump, reset it self is what the seller said I should do,?as I did many times, 8-10 times stalled and waited to continue, then continued, I said won't make it, called the seller & got me a tow truck to get me the rest of the way home,????
So`ss I got to thinking, as I waited it was getting cold in the car, so I started it and turned the heat on high and it idled fine every time, I I reved it no stall so I started driving again the car would start out fine, driving well into the 100km range well but after a few miles again as above said, continued to stall, the motor would putter out slowly and I'd pull over to the side of the road and wait again??but it seemed to be stalling of the transmission, cars wanting to stall moving forward, reminded me of what a friend of mine was describing of his vehicle and not moving forword, transmission drives the unit, transmission has gaskets and o rings that may expand or contract my friend said that he had this similar problem and said seals in the transmission were worn and old and can cause stalling problems, so my Q: is do you think this may be my problem? or something very close to the transmission issue of stalling,?
does this make any sense? to solving this issue of stalling?
have other Pontiac's had similar problems?
waiting answer, iboughtaproblem : (