Engine sputters and runs cold [Archive] - GrandAmGT.com Forum


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01-24-2004, 11:01 PM
SES light went on today, off and then back on. Went on for a day about a month ago, then it turned off.
My engine has been running a little cold, 2-3 tick marks below 200, I have the stock thermostat (original, have 59K miles). Fuel mileage is down a little bit to 18-19mpg.
Engine sputters a little, not bad enought that it stalls out but it definetly feels like it's a little out of tune. Been running this way since around Thanksgiving.
Replaced my plugs & wires in August, Bosch platinums and Taylors from PFYC.

Any ideas what it might be before I take it to the shop?? Going to try to stop by Autozone for a code reading.

01-24-2004, 11:30 PM
Fuel Filter? IF your on your original, your ready for a new one. My engine temperature is always a little lower in the winter, thats not a problem. At 60k, your fuel filter is ready for some attention, see if that helps clear it up. That would explain the poor mileage as well.

01-25-2004, 09:16 AM
Had it replaced around 30K miles. Guess I'm due for a new one.
I put in a can of Techron fuel system cleaner a few months ago, might be time for another one.

01-25-2004, 08:12 PM
Went to Autozone, they said SES light is from a misfire.

Guy told me the reason was I have Bosch Platinums and that anything besides AC Delco will cause an SES light.
Is he right or is that just BS??

01-25-2004, 08:15 PM
Clogged injectors??

Not sure about the plug thing but I stick w/ delco plats

01-25-2004, 08:58 PM
Originally posted by iceman
Clogged injectors??

What's the best way to unclog them??
Just filled up with hi-test to see if that might help, so far it hasn't.

01-26-2004, 07:22 AM
From what I've heard on this site, it's a 50-50 on the Bosch plugs. Some people love them, some say that they get a misfire a couple months after install. I haven't seen a pattern on engine or year. It's possible that some people get the wrong temperature plug for their car. Anyway, another plug/wire swap would be a cheap fix if that's what it was. If that doesn't help, there are threads on this site telling how to do an at home injector cleaning. But 59,000 seems a bit early for a clogged injector.
I'd also change the PCV valve and air filter while you're at it.

01-26-2004, 07:37 AM
Not sure about the plug thing but I stick w/ delco plats

Amen to that. Those Bosch's are crap from my experience. I had a plug completely go out after 2,000 miles. Runnin' on 5 cylinders. After that, I went back to Delco Plat's and I'm not switching again.

02-03-2004, 06:15 PM
Update: had new plugs installed, AC Delco Rapidfires. SES went out the next day and hasn't been on since, idle is far smoother. Engine has a little bit more pep to it. :)

Engine still runs a touch cold, MPG is still down in the 18-19 range, I'll wait until it's a little warmer before I worry about it though. Tire pressure is OK, so that's not the cause.

02-03-2004, 06:21 PM
Fuel filter? Air filter? How's all that stuff?

02-03-2004, 06:30 PM
Originally posted by killerhound
Fuel filter? Air filter? How's all that stuff?

Also had a new fuel filter put in. Cleaned and re-oiled my air filter last summer, will check it out this weekend.

02-03-2004, 06:35 PM
Humm...only other thing that I think of that really could be causing milage to go down like that would be maybe fuel injectors. Someone with better engine knowledge can probably give you better answer, though. I'm just tryin' to help ya out. :)

02-04-2004, 07:22 AM
I noticed an improvement in fuel economy when I changed our O2 sensor, but at 59K, I doubt you'd need that done yet. The cold weather will always make your mpg go down from what it is in the summer though. But, that engine operating temperature doesn't sound right. I'm wondering if the thermostat is stuck open. If that were the case, the coolant would flow freely through the engine without ever getting a chance to warm up. That would also affect your fuel economy since your engine never gets up to its operating temperature.