Thread: sputtering at speed

Okay, I haven't been here in a while but I need help. (if you look at my previous posts you'll get an idea of what I've been through) I have a 2004 GP GT with 146k on the engine (I think, I bought it as a cash car about a year ago and I have no idea if this is the original engine). I have had a #4 cylinder issue for a while but don't have the money to have it torn down to see if the issue is a lifter issue, a dead cylinder or anyone of a thousand very expensive repairs I need done. (Thanks Congress for not extending unemployment) In any event, I do what I can as far as maintenance. Yesterday I drove it about 20 miles for the first time in weeks. Same usual issues but nothing major. Last night I started it again to run an errand and if wouldn't start on the first try. When I got it started it sputtered badly and my misfire seemed more extreme. I let it warm up and put it in gear and it immediately began revving and bucking. I drove it around my complex driveway and when I gave it gas it bucked like someone was pushing me from behind then would idle back down. As soon as I gave it gas again, it did the same.

From what I've read, it could be a vacuum leak, a clogged cat, a MAF sensor (whatever that is), coils, wires, fuel filter, fuel pump, Harry Potter, in other words, anything. Anyone have any insights? Being without a garage and wind chill in the teens outside, it WON'T be fiddled with today and probably not tomorrow as it will be even colder. So I have time to look for guidance from the experts. (read, you guys) I would appreciate any answers you may have.

If it's possibly a MAF sensor I'd start with seeing if it is that as it is easily the easiest thing of that list to check. Remove the engine cover and unplug it and see if the problem persists or changes. If not you can remove it as a possibility.

There that should help you find it

Do I just disconnect the MAF remove it? Secondly, after I remove/disconnect it, do I try to drive it or will the change show park/idle?

Tune up was done about six months ago. changed all the wires and all the plugs. Oil change in September although its over the time needed for another one. Check engine light been on so long I don't even remember all the codes it throws. It goes off from time to time just to trick me I think.

Another question, any suggestions for a good code scanner. Hell, I'm scared to drive this to AZ.

By the way, I want to check if I may have a vac leak. How do you check them?

Okay, here's the latest. Took the MAF lead off, no change. Looked in the hose, looks clean and unclogged. Looked at the throttle body, still clean from the last cleaning about three months ago. Checked my wires, and it seems I have a knock in cylinder three now, always had one in four but now its in three. I removed the wire from the coil and the engine quieted down (relatively speaking).

What I should have mentioned before but forgot. I have oil (not sure if engine, tranny or power steering) in my overflow tank. Checked the oil but does not look foamy or unduly thick. The car runs in normal operating temps, no overheating. My next plan is to do a coolant flush and see if that changes anything. Possible water pump issue? Still need to get it scanned. I started it day before yesterday and drove it around but it ran as it usually does (like crap) with no sputtering. So I'm stumped. Could be anything. What its doing could point to a number of problems, yet all have temp as a common denominator but I don't have a temp issue. (knock on wood)

When was the last time you changed your plugs and wires? Take a spark plug out and look at the gap/general condition of the plug. Also take a look at your air filter, maybe try changing your fuel filter (I got one off eBay for $5 shipped so if you haven't done it yet you might as well it's pretty easy). If all that checks out turn the key in your ignition but don't turn your car on, you should hear a whining noise from the fuel pump, if you don't hear that you might have a bad fuel pump.

Oh, forgot to mention that, the air filter is fine. Took it out and I can see daylight thru it. Its only two or three months old. I'll check my fuel pump today. I do have a leak somewhere around the serp belt but I think its my powersteering pump as I've had to refill it twice now in the last month. That's a minor thing though, can't drive it, so not being able to turn the wheel easily is not a big deal.

Okay, the fuel pump whines so I think that's okay. Sprayed throttle body cleaner around but got no change in idle. Looked closer at the overflow tank and I have my doubts about whether its oil that's in there. Maybe just extremely dirty. I don't really know. I'll let you know, it stopped raining so I can better check now.

Have you changed the plugs/wires since you bought the car?

Changed them about 5 months ago when I had a tune up. Had it done at NTB so I can't vouch for their level of expertise.

Hm, try making sure all the spark plug wires are nice and snug. Otherwise I really don't know what else it could be sorry, I'm not expert by any means though.

I'll do that in the morning.

Okay, after a lot of moving around and not a lot getting done, this is where I am. Pulled a plug AC Delco iridium 41-101 so as far as I've been able to identify no platinum plugs. Attempted to do a coolant flush but couldn't get what I think is the petcock to move. Anyone have an image of what it looks like on the 04 GP? I have the ground effects package so their is a lot of fairings and moldings that makes it a pain to get under the car.

Now, all that being said, I have a leak. Don't know where from or what it is but I see some light brown sludge under the right side of the engine around the belts. Since it has rained the last couple of days, I don't know how much is from the car and how much is buildup from the environment. In any event, when I pulled the radiator cap I found chocolate pudding all over the cap. I don't think its a blown HG because the car runs, it runs like crap but not blown HG crap. I've had that happen to me on a previous vehicle and believe me this problem is NOT that problem. (knock on wood) Here's a pic.