Chevy & GMC Vans

So, over the past few weeks, I've been thinking i was noticing a power decrease. This became especially evident today when I was going up the mountain by my house--routine drive for me... Anyway the power seemed much less, and the van kept wanting to upshift into lower gears to make the hill, as my speed dropped down to 40ish.

What could be going on here? Here are some facts that may be related:

* Van has about 115,000 mi and probably original fuel pump

* Van has in the past year been known to throw a mass air flow code--P0101, i think. Oddly it didn't throw that code
today, but I started backing off on the gas before it could...

* I am starting to get another gear wine out of the rear end

* The tranny doesn't like to cruise at 65mph anymore -- overrun clutches I think

* Plugs and wires are only a year old--pretty new for platinums

* Air filter (K&N) was cleaned about 5000 miles ago.

Anyway my hypothesis is the MAF sensor. Basically, if it doesn't think there is enough air, it won't matter how hard you push the gas. If the fuel pump is dying, I'd have expected the hum like in my last van--never did see a decrease in power there.

Those are my thoughts, but I'd like to hear yours. Let me know what you think could be the culprit here.

Okay, nobody's biting. Either I nailed or my engine is about to blow. This scaring me...

Which is it?

I doubt the engine is ready to blow. That mileage is close to what my van had when I bought it. It now has 189,000 and still runs excellent. As far as I know the fuel pump is original as well as the trans. I think I'd start with the basics. Check the cap and rotor. Replace the fuel filter. Try the Sea Foam treatment. If you have seen the MAF code I would check the MAF sensor. I don't know the specs but someone here should. Maybe the catalytic converter is plugged. I did replace mine. With some maintenence these vans can go well over 200,000 miles.




NRA Life Member

Well it is Sat, most guys are out and about, i'm sure someone will offer advice in the next little while. Is the Cat original, how is the tranny fluid level, Is the fuel filter original as well?

Cat is original--never seen one go that fast--tranny fluid level is okay, fuel filter is a year old.

Check for a broken wire at the MAF sensor connector. I've seen that a couple of times, hangs on by a strand and causes intermittent problems.

Scott

sfeaver wrote:Check for a broken wire at the MAF sensor connector. I've seen that a couple of times, hangs on by a strand and causes intermittent problems.

Scott

That's not the issue either. Also, I tried unplugging it and running like that just to see. No changes in performance.

Currently my van feels like an overloaded 18 wheeler going up hill. The problem is getting worse. It keeps upshifting and is now loosing speed up hills in second gear, with the gas pedal mashed to the floor.

Also when the pedal is mashed, it doesn't want to shift out--probably because the engine is not giving enough power to make that happen. It will shift fine when driven easy though.

Thoughts?

I was just down the mountain again today. It didn't make sense to kill my van on the way back up, so I hit advance and swapped out the MAF in their parking lot. Problem mostly solved...

A little birdy later told me that KN filter oil could have simply fouled up the sensors...did I just wast $130?! ](*,)

Well either way, problem solved. Time for a Guinness