Now another problem has occured - surge and stall at idle

So, I think it's one of 2 possibilities. Last night, went out and started the Riv, and it began to surge at idle in park. Through it into gear, and it surged more than stalled when the gas wasn't being pressed. Go out this morning to see if possible vac leak and I started and it ran and idled better - not perfect but it didn't stall in gear.

So I'm leaning towards either crank sensor or MAF sensor. Maybe fuel pump going out? What say you guys. mileage is 152,000

What have you done recently? Have you touched anything under the hood before this started?

I tend to think dirty MAF sensor, but vacuum leak is always a possibility.

Well, the transmission was recently done but I haven't had any problems in that area. I really believe this is a seperate issue and from what I've read here, no codes being thrown and the fact that after a cool night it started just fine, really suggests that to me that the crank sensor is the issue. It's never been changed and it does sound like a common problem.

I thought vacuum leak but not sure how that would correct itself overnight. MAF sensor throws codes immediately from what I've read and like I said - nothing.

Hows youre fuel pump?

A crank sensor would throw a code and cause a miss fire if im not wrong

Why should you have to guess at this. Test first, then replace parts if you find something suspicious. Test the fuel pressure with a gauge. Then hook up a vacuum gauge to the engine. At idle, in Park, fully warmed up, it should pull 20" of vacuum.

Not trying to guess - just trying to narrow it down to 1 or 2 possibilities. I figured symptoms seem to be the same throughout these cars and certainly someone has had this issue before me.

playa wrote:

Not trying to guess - just trying to narrow it down to 1 or 2 possibilities. I figured symptoms seem to be the same throughout these cars and certainly someone has had this issue before me.

They are simple tests. I have to tell you Mark, there are a lot of guys on the Buick boards that I frequent, that just change parts, and spend more money than they have to. It's a very frustrating thing to throw money at a car hoping you will be right. Just because someone else has a symptom in common with you, doesn't mean it has the same cause. The reason the FSM is so huge, is because of the complexity of the systems in the car. Different defects can cause similar symptoms. That is why the troubleshooting tables are so valuable. They narrow down the causes, and eliminate wrong turns. Time consuming, yes, and that is why diagnostics cost so much when you bring the car in for service. A vacuum gauge is a very inexpensive, and extremely useful tool to have. My boost gauge is also a vacuum gauge. Fuel pressure is very important for any fuel injected cars. They have very small ones that screw right on the fuel rail.

BTW, I would not suspect the crank sensor with your symptoms. It is much more likely that you have an IAC problem, or a dirty carbon buildup in the throttle body. I would clean the throttle body and the MAF while you are in there. A fuel pressure check will tell you whether you have to change the fuel pump.

Larry, you are right that one can spend a ton of money guessing and changing parts. I've always tried to stay ahead of the curve with the Riv in that respect. I don't mind changing parts before their time has come just a preventative maintenance.
These parts were on my short list of things to come
Fuel pump
Crank Sensor (and with that, the HB)
Intake manifold gasket
Testing the fuel pressure is not a problem and changing the pump is easy too. I'm just surprised that is your diagnosis. Fuel pump would throw a code and this has not. Maybe it's jsut a fluke I will post back and tell you what I find.

MAF sensor was the issue.

How did you finally diagnose it?

I scanned for codes again and got one. Maybe we have it somewhere but if not, It would be awesome if we had some type of flow chart set up with symptoms and possible causes. Those MAF sensors are expensive though

yeah.they are. have you tried this before buying new maf?