So i have been searching for a while now. Most people have starting issues when the car is warm, mine is the complete opposite.

When i first start the car it will turn over and try to run. But it never gets a chance to idle for more than 1-2 seconds before dying.

If i hold the gas pedal to about 1000-1500 rpms for about 1-2 minutes i can let off the gas and it idles at about 900 rpms and runs fine. No power loss, no hesitation.

When i first got the car, it would start and the rpms would race. After replacing the IAC, it started with this problem. Thought maybe it was faulty so i replaced it 2 more times with the same results. I've replaced the TPS as well.

Any ideas would be greatly appreciated .

 

Hi, and Welcome to MCF. What's your Name or what do you prefer to be called?
Do you have any codes? When you replaced your IAC did you use an AC/Delco part. Your sensors should always be Delco because the PCM is Very Sensitive! I would also check your TPS for proper operation.
Another question is how does it idle once it is warm? Like at a stop sign! Your IAC also controls that.
Other than that, if you have no Codes, I would say take it to a shop that has a Tech II scanner and have it read. You could have codes stored that are not causing your CEL you come on.

 

My names Jim. Most people online call me ego lol.

I replaced the parts last year. So I honestly don't remember the brand. The last code it threw said idle was to low.

Once its warm it idles fine. Around 900 RpMs steady at stop signs and lights. No hiccups or sputters. Plenty of power. It is getting pretty terrible gas mileage. About 13 around town.

 

Unplug the mass airflow and see if it starts normal. I had a TPI Camaro acting like that. But it also threw a code , anyhow unplugged it and it started fine or better I should say. Replaced it and no more check engine light and all was good.
But like stated those sensors in my personal experience while more pricey most times are better off ac delco/gm vs aftermarket.

 

Hi Ego,
Don't go buy what your info center, above your head, says your gas mileage is. From what I've seen and read here, they are not very accurate. Do the math!
I would go ahead and replace the IAC, with an AC/Delco one. With rough idle only on cold starts, it really sounds like that is your problem. You may have a MAS problem too. Do you know anyone, or have yourself, a Tech II Scanner? It will not only read your codes but it will give you more detailed information on the cause. It can even give info on the operating perrameters of your sensors. If you don't what to do the trial and error methood, that would be the best way to go cause it will tell you exactly where the problem is.

 

Tires disconnecting the MAF no changes. Had someone scan the car. One was left rear wheel sensor.

Other was idle low. ( forget the code got it written down in the shop.)

When I fill up it holds around 17 gallons. I get roughly 235 miles around town. So it is around 13-14 town. I heard people get 16-18 around town?..

I will try using the delco sensor. Will pick it up tomorrow. I'm use to working on older cars. These things with computers can sure be a pain.

 

I learned on old school cars, 70s and 80s Chevys mostly. The new imputed controlled cars are not as hard as you think. Most of the time when you get a code, it's the part or the sensor related to it. Of course you still have your bad belts, bad muflers, fuel filters and some other things that don't through codes, directly but that's when you fall back on your old school knowledge.

 

Well, i had someone else bring a different scanner and scan the car.

Here are the other codes it threw since then.

p0420
p0440
p0507

As well as

c1245
c1216

 

Your cat is probably plugged.

You have EVAP leaks, or a messed up vent valve/solenoid.

And an IAC problem.

Should probably check for vacuum leaks while you're at it.