My 2008 Impala SS is a bit of a drama queen lately. Keep her in the garage and she is happy, park her outside in the cold... she throws a fit. It only has issues on cold starts, and only when it's cold outside (the colder it is, the worse the condition). A normal start takes see:
*The starter spins fairly well, I'd say on average 5-25% slower than a warm crank. The colder it is, the slower it seems to crank. I can't rule it out, but I doubt it's weak or bad (although it is the original at 133k). Nonetheless, it does audibly sound slightly slower than a warm crank. When it's warm it does crank in it's usual time/speed/sound.
*The battery was replaced in the last ~12 months. No issues there, it cranks excessively, so I know it's not a power issue. *Plugs are Delco iridiums and were changed at 80k, wires done at the same time. Runs perfect once started, cold or hot, cruising or racing. Ruling out spark.
*That also makes me believe it's not a fuel issue either, but I'm not too confident saying that. I always use Top Tier 91 E-0 (NO ethanol), and run Techron religiously (at least once per 4k mile OCI).
*Air filter is factory paper and was changed about 15k miles ago. Looks good, doubt it's an air issue.
*Oil is the spec'd 5W-30 (Valvoline Synpower). It's not thick/old/low oil.
*Remote starting the car doesn't make any difference versus manually starting.
The only interesting info I can offer is when it's cranking, if you press the gas pedal very lightly while it's struggling, it seems to help it fire. But this car doesn't have a throttle cable, it's electronic. So maybe the gas pedal is a placebo?
I was hoping it would give me some sort of hint, perhaps a code/light, but no. Nothing other than these observations. Common sense says it's air, fuel or spark. None make sense. It runs perfectly once it's started. My best guess is it's either starving a bit for fuel on startup, or it's a starter on the way out. But both just don't make sense. Any ideas? Thanks in advance!
*The starter spins fairly well, I'd say on average 5-25% slower than a warm crank. The colder it is, the slower it seems to crank. I can't rule it out, but I doubt it's weak or bad (although it is the original at 133k). Nonetheless, it does audibly sound slightly slower than a warm crank. When it's warm it does crank in it's usual time/speed/sound.
*The battery was replaced in the last ~12 months. No issues there, it cranks excessively, so I know it's not a power issue. *Plugs are Delco iridiums and were changed at 80k, wires done at the same time. Runs perfect once started, cold or hot, cruising or racing. Ruling out spark.
*That also makes me believe it's not a fuel issue either, but I'm not too confident saying that. I always use Top Tier 91 E-0 (NO ethanol), and run Techron religiously (at least once per 4k mile OCI).
*Air filter is factory paper and was changed about 15k miles ago. Looks good, doubt it's an air issue.
*Oil is the spec'd 5W-30 (Valvoline Synpower). It's not thick/old/low oil.
*Remote starting the car doesn't make any difference versus manually starting.
The only interesting info I can offer is when it's cranking, if you press the gas pedal very lightly while it's struggling, it seems to help it fire. But this car doesn't have a throttle cable, it's electronic. So maybe the gas pedal is a placebo?
I was hoping it would give me some sort of hint, perhaps a code/light, but no. Nothing other than these observations. Common sense says it's air, fuel or spark. None make sense. It runs perfectly once it's started. My best guess is it's either starving a bit for fuel on startup, or it's a starter on the way out. But both just don't make sense. Any ideas? Thanks in advance!