2000 Chevy Astro running rough - loses acceleration. Bad gas? Ethanol?

My 2000 Chevy Astro van started having problems whenever I accelerate, hesitating losing speed, and all I can possible tie it to is a new gas station where I filled up which said “May contain ethanol”. I think the “service engine light” flashed on for a second but does not stay on.

Could bad gas or the ethanol be the problem? Gas pumped was in North Carolina. Would getting the problem codes read for free at a parts place help?


yes get codes read first then go from there.

Ok I got my codes read and there was a reading “P0174” I went online and found a web page that addressed that issue.


It involves a lot of using a scan tool. I hope the parts place that read it is not trying to sell me a scan tool! At the same time the engine problem started I also noticed I had a flat today and my nearby tire shop told me I had one nail & one needle in my tire but they were able to patch it. this happening at the same time makes me suspicious.

Also the “service engine soon” light was on and the guy at the auto parts store told me that was just something that came on at certain mileages.

The MIL “service engine soon” lights isn’t something that just comes on at certain mileage. He’s probably way out of date. He’s probably thinking of those lights that came on at specified mileages to prompt you to replace the oxygen sensor. But that’s going way back.

So, here’s my opinion, based on what you posted and my personal experience:

You HAD a misfire, at least for awhile. A flashing MIL means a misfire severe enough to damage the
catalytic converter.
The P0174 means bank 2 was running lean, quite possibly due a misfire on that bank.
You have the CSFI fuel injection system, which had some issues. Fuel injectors would get stuck and plugged. GM had plenty of bulletins explaining how to test, diagnose, clean and replace it.
GM eventually came out with a drop-in replacement fuel injection assembly (which actually wasn’t that expensive or that big of a deal to install).
But first, they wanted you to attempt a cleaning.
That’s what I would do in your case. I would add some fuel cleaner to the tank the next few times you fill up. Easy enough, right?

If that MIL comes on again, you should consider getting it professionally diagnosed. And don’t be surprised if they mention that your fuel injection assembly (they may call it a spider) needs to be replaced.

This has all been speculation, based on what you posted and on my personal experience working on
vehicles with your fuel injection system.

Thanks very much for your suggestion. The van starting running better and then my alternator went out so I am dealing with that right now and hope it may be causing the other issue { I doubt it however!}

@Dugitsbane Glad to have been of help.

May we assume the check engine light is no longer on and the van is no longer hesitating?

I recommend installing either a very high quality alternator (AC Delco or Remy) if you let a shop do the repair.

On the other hand, if you’re installing it yourself and want to save some bucks, install something with a lifetime warranty, in case it fails again.

Two more things.

Seriously consider replacing the belt. Now’s a good time time to do it.

Make sure the battery’s in good shape. If it’s 4 or 5 years old, replace it now.

The times the van hesitates are much less frequent but quite startling - it seems like the idle speed goes off and I pump the gas a few times to get it kick back in. Hope the new alternator helps.

Yep, I started another topic on the alternator but it has not come up yet. I went too long between beers on a Saturday or just spaced out when I had problems putting the new {3 year warranty} belt on. I found out I was just trying to route it incorrectly however. Weird, I did ok on the gears and pulley questions on those aptitude tests! I have not put the whole thing back together yet and wonder if it will run without the sensors{?} in the air hose intake being reassembled. I bumped the starter before putting all the fan shroud & stuff back and nothing broke so I guess the belt is ok.

Thanks again for your comments.


Here’s some ideas, and I know it’s a PITA . . . because you have a van

Clean the throttle body

If that doesn’t help, consider replacing the idle air control valve

I installed the alternator over the week end and so far everything is running fine. Answering my own question I found you can’t run the engine for long without the “mass air sensor” do hickey in the air intake tube hooked up - it shudders to a stop.

Thanks for the help and I am glad the threat of imminent terror is over for Boston and I everyone who suffered from this recovers quickly. There were several people from our area of N.C. who were maimed in the blasts.

@Dugitsbane glad to hear your van is once again running fine.

Sorry to hear about your injured neighbors.