Buick Regal Idle Problem


#1

OK, I have a problem I can’t figure out.

2001 Buick Regal with approx 250,000 miles. 3.8L V6. Non supercharged It’s my son’s car. Used to be mine, I bought it with 19,000 on the clock.

The battery succumbed to the cold weather last Monday. On Tuesday, I put a new battery in, which itself now works fine. However, since then, the car refused to idle decently. It’ll idle right after startup, but once you put it in gear, it’ll die. When you start it, it seems to idle normally, you can let it warm up a bit and it’ll settle down to about 900 rpm. BUT! Once you put it in gear, it’ll stumble and die.

This problem started after battery replacement, so I have to wonder if it’s somehow related to that. It ran fine before the battery died. I checked everything over thoroughly, and visually everything looks OK. No loose wires or hoses, etc.;

Today is the first time I’ve had to work on it since the new battery, so I thought I’d get it out there. I’m getting ready to go put a scan tool on it and will report back with those results.

I’s appreciate any ideas you guys may have.


#2

@DrRocket

This sounds like a GM truck I had at work recently, a 2003 Sierra 2500 6.0, by the way

After installing a new fuel pump, the truck started right up, and idled pretty well

Once you put it in gear, it stalled out

Cleaning the throttle body resolved it


#3

Ok, just got the error codes.

P0101 and P0108, which point at the MAP sensor. The thing is, I put a new one in about a year ago. Would it have gone bad that quickly, or perhaps there are other issues I’m dealing with?

The bigger issue now is whether I’m actually going to even keep this car. I bought it in 2003, and it has over 250,000 miles on it and counting. I think I’ve gotten my money out of it. It has other issues that I’ve been nursing along, hoping to get one more winter out if it, but I think I’ve reached the end of my rope with it.

I replaced the exhaust a month ago, and noticed then that there was a very faint light hum that I determined to be the right front hub bearing. Well, today was the first time I’ve driven it since, and it’s become an unbearable howl. (He didn’t say anything about that!) Plus, it needs a windshield, struts and alignment. Not only that, but rust is starting to claim the rear quarters.

I’m thinking I’m done throwing money at this thing. It was a great car. I really liked it quite a bit. Will be sorry to see it go. :frowning:


#4

The P0101 is for the MAF not the MAP. The P0108 is for the MAP. And neither of those codes tells you that the sensor itself is THE problem. Both refer to a high voltage condition. That CAN be caused by a sensor problem - but hmmmmm…I wonder where that voltage comes from? It’s time to check the wiring. I’d also clean the MAF sensor, and as long as you’re tinkering the throttle body and IAC as well.

You should also check for vacuum leaks. None of the above costs more than about $10 in supplies.

Do note that the MAF and MAP do similar things and the MAF code CAN get set if the MAP circuit is squirrely. So it still may be a MAP sensor system issue


#5

Since we tend to whine a bit when posters never give us updates, I thought I’d post an update on an issue I was having.

My son bought another car and gave the Regal back to me after ^ this ^ happened. It sat out the winter in my driveway. (Thanks son!)

So, we had a 60 degree day last Sunday, and I decided to get to the bottom of the idle mystery. As I said, I’d replaced the Map sensor in the manifold last year. I took another look at it, and relized it was pretty loose in it’s mounting. I removed it from its mounting, along with the mounting socket itself. That’s when I relized that the bellows type seal had somehow gotten pushed down into the bore of the mount, rendering it useless, and thus the sensor inoperable. I removed it, coated the outside with a very thin coat of vaseline, and reinstalled everything, ensuring that this time the seal remained where it was supposed to be, and that the MAP sensor fit snugly in the mounting. Restarted the car and it still idled poorly. Thinking the computer was operating on bad information from before, I disconnected the battery while we installed a new right front wheel bearing. Once that was complete, I reconnected the battery, started it up, and the car was its old self again! :slight_smile:

It now starts right up, idles perfectly, and the front wheel is no longer howling. It could still use new struts and an alignment, the valve covers are leaking quite a bit, and I noticed that the rod ends could use replacement as well, but all of that wouldn’t be tough to deal with. I’ve decided to hang onto the old girl for a while longer, as it’s now a viable car again.

Even if I do eventually decide to sell it, I’ll still get quite a bit more money for it than I would have before.