Hello,

I've heard20 different things to try lately and I'm ready for someone who knows what they're talking about.. plus im a poor boy who needs to fix it quick and easy. I am very electrical inclined (inside the car) but I have no clue if it's mechanical.

98 Camaro, V6, 116,000. All stock aside from exhaust, battery, wheel and tire upgrades. I bought it with 103k this spring.

Here's the deal, if it's warm out (50degF) or warmer, this car starts perfect andruns it's heart out.

If it's cold (40 and below), and it sits overnight.. in the morning it will fight me to the death about starting and staying running.

We've put a new starter, fuel filter, oil change, driveshaft, and coolant temp sensor in it in the past month.

It acts like it's just choking itself out. Once the starter grabs, I have to keep the RPMs up above 2000 for about 5 minutes or keep the rpms up and slam it in gear and take off down the street and it will spurt and sputter down the road but as soon as it gets warm, it goes back to normal and will drive perfectly no matter the distance. After it's been warmed up once, you can start and stop the car perfectly as many times as you want until it sits overnight. Then it's back to choking.
It isnt spitting anything out theexhaust but it pops very loudly while cold starting it and keeping the rpms up.
I really don't think its choking on gas because just from putting up with it for a month or better, it's really not burning up lots of fuel.

If it's ultra cold, it wont start and stay running for anything and I just run the battery down trying.

Anyyyy help would be greatly appreciated. I'd be happy to supply ANY other info needed. Thank you.

 

Check engine light lit? Three sensors I am thinking of are Intake Air Temperature (IAT) sensor, Mass Air Flow (MAF) sensor, and Manifold Absolute Pressure (MAP) sensor.

 

I knew I forgot to post something... and a couple other things i forgottoo.

Engine light: Yes and no. Occassionally it will come on, but the only code it throws is random/multiple cyl misfires.. which I totally understand with the way it acts. But it doesn't throw it all the time and usually two starts or so after, it's gone. And even on bad starts, sometimes not at all.

also put in K&N drop in replacement air filter this summer.

And could be totally unrelated::
-Temperature gauge. I noticed the other night the temp gauge was apparently not working because I took it on a long drive and never got off pinned cold. Thats why we tried the coolant temp sense. Did not fix the problem.

-Air.. it gets warm, but never HOT. Will get cold. Blowers work at all speeds and all directions.


Other explains... Driveshaft.. the factory 2 pc stripped out, replaced. Fuel filter... shot in the dark as a fix, no change. Oil change.. it was just due.Starter.. helped get it to fire up better but still not fixing the staying running til warm.

Ideas people have given: Spark plugs? O2 Sensors?

Thanks again.

 

O2 sensors are monitored during open loop, but are not used as input until you get to closed loop. These should not be the problem if it is only during cold starts. I would check actual temperature of the coolant, as opposed to gauge. Sounds like two possibly unrelated problems.

 

Start with plugs & wires first, then some MAF cleaner, if still an issue check fuel pressure, which could be a fuel pump or regulator problem. Check codes at a shop with diagnostics + flow charts - maybe a bad/clogged fuel injectors? Try a few tanks of Lucas injector cleaner. On the separate heat/coolant issue, install a Prestone flush kit & do a super flush, sounds like your heater core may be plugged, replace the thermostat.

 

I'm pretty sure that it's your plugs and wires. I had the exact same issue a month or so ago. Swapped out the plugs and wires and it was a new car. Be sure to properly gap your plugs and make sure your wires are connected to the right cylinder as you replace them. Sounds stupid but it's easy to screw up wire placement if you're doing this in a hurry and have more than one wire pulled. But yeah swap out the plugs and wires and you should be good to go and like I said I had the exact same behavior you describe with my Camaro and the swap out fixed it. Good luck and let us know if that fixed it.

Thanks,

Tom

 

Allllll right. Got the sparks and such changed out at 6pm. I just tried starting it at 11:30pm and it's already back to it's old self, choking, popping, dying, cranking, and having to get it warm.. then it was fine all the way to town and back.

The plugs we pulled out were pretty nasty and fairly gas covered..

..but in the end appears not to be the answer.

Neeexxxxxtttt?

 

Okay so this afternoon we changed out the thermostat and the Intake Air Temp Sensor.

I have hoooot air and the temp gauge on the dash is working again.

I took it out for a little while today and the car is running probably as good as it ever has.. (probably due to all the *%&^ done to it lately).. but really good and has started up and stayed running great all day. Will give it the true test in the morning. Wish me luck!

 

..and still crappy. Gah.. I cant afford to change MAF if it's not going to fix my problem. Any other ideas? Scrap it? :P

 

If you want to check the MAF, unplug it before you try to fire it up. Car should change over to running on manifold pressure instead. Should be able to diagnose assuming the MAP isnt bad. If it is still acting the same, MAF isnt your problem.