Low RPM/Cold stutter

[sparker]

Hi Guys,

calling upon the boards vast experience to see if anyone has had this problem before. As we hit winter in Australia here a week ago the temperatures in the morning have been quite cold. I am noticing (until my car warms up) that it stutters and even backfires sometimes when trying to drive at low RPM (as in, taking off from a stop). If I give it a heap of revs its ok and once warm its ok as well.

I have a couple of suspicions, but would like to know your thoughts. Firstly, its a 97 2.5l with an underdrive pulley, an intake that I made from carbon fibre and a pedro exhaust (full)

I am thinking its either the battery starting to go (low RPM, little alternator support and cold weather), spark plugs needing to change for the cold temperature or possibly perhaps my MAF sensor?

Any suggestions!

Sam

[Bladecutter]

Is your CEL light up on the dash?

Start with the spark plugs, and inspect the ignition coils for cracks/damage while you have them in your hands.

BC.

[thstone]

Based on your description I'd start with cleaning the MAF, but either way you've identified all of the likely suspects.

[sparker]

Yeah I thought MAF could be worth a try, possibly got a little dirty from the new inlet and filter. I bought some CRC MAF cleaner last night, but it was raining (and my garage is a work site at the moment) so didn't get a chance to try it out yet. Hope thats the problem!!!

If I were to look for cracks in the coils, can you describe (or show if you have pictures) the type of crack that could cause this? As in, would it be very obvious or do I need to inspect very very closely for hair line cracks?

Regards,
Sam

[sparker]

Oh - forgot to mention, no CEL and no codes when scanned. But there is certainly something going on!

Sam

[mikstew]

With my recent experience, I would also suspect the MAF, but would expect a CEL.

Note that you need to put some time/kms on the car for it to throw the CEL code, which is why your scan may have turned out negative.