Error code P0171/system too lean????

I'm new to the forum, and I hope someone else might have had this problem and knows how to fix it. I have a '99 Honda Passport, which is essentially an Isuzu Rodeo. My check engine light just came on a couple of days ago. My oil change shop hooked up the machine and P0171/system too lean was the problem. I've also noticed that my car revs up on it's own lately, and it acts like it wants to die every now and then. Does this sound familiar to anyone? If so, what do you recommend that I try first? I have not taken it to a dealer yet.


Thanks in advance.

This is almost certainly a bad intake manifold gasket. Super common on the 1998+ 3.2L. Any shop that works on these trucks regularly will be very well versed on replacing the IMG. Search these forums on it & you'll find tons of stuff.
G/luck
Joel

That's what my research has found, but I wanted to check with some you guys. You seem pretty knowledgable.

I'm new to the forum, and I hope someone else might have had this problem and knows how to fix it. I have a '99 Honda Passport, which is essentially an Isuzu Rodeo. My check engine light just came on a couple of days ago. My oil change shop hooked up the machine and P0171/system too lean was the problem. I've also noticed that my car revs up on it's own lately, and it acts like it wants to die every now and then. Does this sound familiar to anyone? If so, what do you recommend that I try first? I have not taken it to a dealer yet.


Thanks in advance.
I am having the same problem with a 2000 Rodeo except I also get codes reading too rich on banks I and II. It is not the gaskets because I have had them checked. I have heard it may be a problem in the Idle Air Control sensor or valve. My problem is the pictures in the repair manual don't look anything like the actual throttle body. Good luck.

I am having the same problem with a 2000 Rodeo except I also get codes reading too rich on banks I and II. It is not the gaskets because I have had them checked. I have heard it may be a problem in the Idle Air Control sensor or valve. My problem is the pictures in the repair manual don't look anything like the actual throttle body. Good luck.

Mark, I doubt it's your IAC. That will just lean you out & give a rough cold idle if anything. A rich condition is more likely a problem with your mass air flow sensor (MAF). Are you running a reusable/oiled airfilter by chance? Those foul up a rodeo MAF in no time. You can try to clean the MAF probe with electrical contact cleaner & cotton swabs, but most of the time they need to be changed out.
G/luck
Joel

So since I have the same problem, I was wondering what you ended up doing and if it worked. I'm leaning towards intake manifold gasket. I clearly have an air leak somewhere and the fluctuating idle. I'm thinking about doing the job this weekend, hopefully its not too difficult for the average diy'er.

I have a 98 Rodeo with the 3.2 v6. Just two days ago it started to idle wierd and will almost die and sounds like it is running rough. I opened up the hood tonight while it was running and hear this air hissing noise. It sounds like the intake manifold gasket that I keep reading about. I have read both the Haynes manual which makes it sound pretty difficult, and the posts on this site which doesn't sound too bad to do yourself. I would also think about doing this job this weekend if it is something an average do it yourselfer can do. Any other comments about the effort this takes would be appreciated. How much do this gaskets cost anyways. Should I go to the dealer or someplace like OReily's?

I think I am experiencing the same kind of problem. At idle, it runs a little rough. If you are say at a stop light and ease of the brake to let the car inch forward, it is extremely rough. Also, the other day I got back in it after going to a store, so I would not say the engine was cold, and it shut off 3 times, like it was out of gas. The only way I kept it started was to rev it up high and hold it for a minute and then let off and it idled and I kept going. I had it running and was manually reving it up and letting go. It stutters badly and acts like it wants to shut off. Is this like the problems you encountered? My brother is a mechanic and has a computer to hook up but lacks the software to narrow it down exactly. If I can escape going to the dealership, I will greatly appreciate any help. I am thinking either MAF sensor of IMG. What do you think?

I had the same code happen to mine too, but it's only when it accelerated hard and pass 80 MPH. This was happen every time when my son took truck for a drive. All I have to do just reset it. If you were me. I would try some thing easy DIY, like Fuel regulator or clean MAF. It's within reasonable price and easy to work on then replace IMG. Good Luck.