No power on start

[MountainManJoe]

Hey guys. Lately I've been experiencing this annoying problem, and it seems to be getting worse.

After starting the van, I put it in gear and hit the gas, but it just doesn't want to go. It doesn't have any power, and moves at about 10 Km/hr. It accelerate very slowly and unevenly, causing the van to lurch forwards. It sometimes sounds like it's going to die, but it never actually does. It doesn't matter if I am pressing the gas lightly, or have it floored, it seems to go at the same speed. It does this for about 30 seconds, and then suddenly picks up and takes off, and everything seems normal until the next time I start it up. The engine starts perfectly on the first crank, every time. It doesn't matter if the van has been sitting a few days, or a few minutes. Any thoughts? Thanks in advance.

[LiftedAWDAstro]

Any SES light? Can you check for codes? Have you checked the fuel pressure? How about the air filter, plugs, wires, cap and rotor?

[MountainManJoe]

No SES light. Air filter is fine. If there was an ignition problem, wouldn't I notice more frequent problems or DTCs?

[astrozam]

Checked your tranny fluid level lately?

[MountainManJoe]

Transmission fluid is all there.

[astrozam]

Transmission fluid is all there.

What happens if you start the van,let it warm up for a few minutes THEN put it in gear and drive away?

[Smiliesafari]

Put a fuel pressure gauge on it. OR, change the fuel filter.

[MountainManJoe]

I'm not 100% sure, but I think it's only doing it when going uphill. Will investigate further...

[MountainManJoe]

A similar thing happened to me recently, under different circumstances...

I was driving along the #1 through the rockies, and after a long uphill I coasted to a stop because of construction. I turned off the ignition. Once traffic started moving again, I once again began experiencing power loss. On a level stretch, I couldn't seem to get the van going faster than around 90 Km/hr. This problem persisted for some time and I seemed to just crawl up the hills. It was very confusing and I couldn't tell if it was something with the motor or transmission, but I THINK wasn't getting 4th gear either. I decided to stop in Golden since I needed some supplies anyways. After that when I got back on the highway, the van started running normally again. I don't even know know if this is related to my original post or not, but I thought it was worth mentioning.

[MountainManJoe]

I replaced all the transmission fluid and filter before the weekend and then went on a trip. I had the same lack of power problems on the highway again. I was also driving through deep snow, and when I would be stuck ,the wheels would stand still with the engine at full throttle (= major slippage in torque converter). I also notice problems upshifting when the engine is under high load. I'm beginning to think this is a tranny problem.

[MountainManJoe]

OK, so now my SES light is coming on. The light is solid but comes on at random. Sometimes I can get away with making a trip without it coming on, but it does illuminate more often than not. It is also getting worse. This is the code:

DTC P0101 Mass Air Flow (MAF) Sensor Performance

I had to get my Aircare done today (emissions testing), so I took the van out on the highway to get it good and hot. Then I climbed a steep hill, and boy did it struggle. At full throttle the engine roared, but wouldn't go over 100 Km/Hr, and gradually slowed down. If I eased on the gas a bit, it would drop gears, but then went even slower. The tow/haul switch made no difference. Even when I went back down the hill, it didn't want to accelerate. The lack of power problem is definitely worse when the engine is hot. Thankfully (and strangely), the SES light never came on and I passed the test.

I took apart the intake and looked inside. I was hoping there would be an easy fix like cleaning off gunk. Here's what I saw ...



As you can see, there are thin rails running across the intake body, with tiny resistors or "hot wires" mounted between them. What I want to know is, are there supposed to be 3 rails and 2 resistors on each side? (which also makes me wonder if one was sucked into the engine.)

[LiftedAWDAstro]

I hope you didn't touch them! If you did they are probably screwed. Also make sure you put the MAF unit in so that the tiny sensors are towards the intake. Double check the air hoses are all tight as well.

[MountainManJoe]

No, I didn't touch them, and yes, I put everything back nicely.

My drivetrain warranty apparently doesn't cover sensors (a lot of good these warranties are!)
I looked at some pictures, and the sensor looks as it should. A new one costs around $300. Some say that degrading performance can be caused by this thing getting dirty. Well I don't see much buildup on there, so I don't see how it could make my van drive THAT crappy, but I sure don't want to spend want to spend 3 bills. Has anyone got experience with cleaning these things? If so, did you notice a difference?
Could anyone give me a normal range of values for the airflow, that I can use for comparison if I hook it back up to a computer?

[mikedamech]

These had ign. switch problems. My sister in laws 2000 would not go into 1st or 4th gear, was in a limp in mode. She took it into the dealer and that's what they replaced. I told her it was probably the tranny and not to take it to them but was glad they helped her out.

[MountainManJoe]

These had ign. switch problems. My sister in laws 2000 would not go into 1st or 4th gear, was in a limp in mode. She took it into the dealer and that's what they replaced. I told her it was probably the tranny and not to take it to them but was glad they helped her out.

That's an interesting theory, Mike. Is there a way to test it to see if it's working properly?