Cleaned Mass Air Flow sensor, now it's trying to kill me...

[MacLaddy]

1999 Limited. 3.4L

Hello all,

So I'm stumped. Gunner has been running a bit rough for a while now, kicking up a random error code here-and-there for a misfire on cylinder 6.
I figured I might as well clean the MAF to start with, as I've seen that is a common problem, and it definitely fixed any rough running. Now it is just ramping up to about 3500 RPM's and staying there. Luckily, I had the presence of mind to turn the key off before it ran me into a tree earlier today.

Any ideas? It is not pulling any codes now, but as I said it is idling extremely high. I can give a little torque to the TB to slow it down, but it doesn't go as low as it should, and ramps back up the next time I push on the accelerator.

Did I break something? I don't see any obvious vacuum leaks that I may have caused, but I'm not ready to rule anything out. I couldn't remove the MAF due to stripped screws, so I removed the entire air filter assembly & cleaned it that way.

Any thoughts are appreciated.

Thanks,
Mac

 

[slides]

what did you use for cleaner? its plugged in right?

 

[Weagle2]

I had a jeep do this once when I had a bad battery. It was causing computer to malfunction. Check your battery.

 

[MacLaddy]

what did you use for cleaner? its plugged in right?

CRC Mass Air Flow Sensor Cleaner. Yeah, it's plugged in. Yes, I double-checked because I often do stupid things like that.

I had a jeep do this once when I had a bad battery. It was causing computer to malfunction. Check your battery.

Battery is low. I've had quite a few issues with it the last few days. Why would/could that cause this issue? I'm getting good charging voltage, so shouldn't the alternator handle any computer functions once running?

 

[Brino1]

Throttle position sensor possibly?

 

[MacLaddy]

Throttle position sensor possibly?

That is what I am starting to think. Can you, or anyone, enlighten me on how the Throttle Body works? Is there a motor on the inside of that that makes adjustments? The reason I ask is I have noticed now that my gas pedal, and hence cable, is clearly slack. The pedal goes about halfway down before grabbing, which corresponds to about an inch of slack on the throttle body.

The accelerator turns it CCW. There is nothing I can see keeping it from turning back CW, even when I try to do it manually. That's why I am wondering about the interior of that component.

Mac

 

[Brino1]

I can't help ya there bud.Ive heard of guys having them rescaled but not sure how that's done

 

[drallan]

I would recommend finding a way to remove the MAF properly and cleaning it. When I bought my 99 I did something similar, but w slightly different results. I tried cleaning the MAF thought the air box w/o removing it properly and ended up w/ truck that would bog down significantly under acceleration. The truck drove ok when I bought it, but I felt the need to give her the once over. I sprayed some TB cleaner into the TB and some MAF cleaner into the air box, afterwards I experinced some problems. Tired changing, plugs, coils, throttle body, IAC, etc to no avail. No codes, no anything other than a big hesitation when stomping on throttle, I know it's the opposite of your problem, but the sensors can be a tricky issue. Finally I removed MAF and saw a big hunk of dirt attached to it, cleaned it and have been money ever since. I would bet you blew some garbage onto the MAF wire and need to remove it and give it a proper cleaning (not just trying to blow through air box holes). I ended up using a dremel tool to cut a slot in the screws then a flat head screwdriver to remove MAF screws.

 

[IBallEngineer]

That is what I am starting to think. Can you, or anyone, enlighten me on how the Throttle Body works? Is there a motor on the inside of that that makes adjustments? The reason I ask is I have noticed now that my gas pedal, and hence cable, is clearly slack. The pedal goes about halfway down before grabbing, which corresponds to about an inch of slack on the throttle body.

The accelerator turns it CCW. There is nothing I can see keeping it from turning back CW, even when I try to do it manually. That's why I am wondering about the interior of that component.

Mac

Well if the pedal is doing that, check the throttle body to see if it is closing, also look for vacuum leaks near the IAC motor, and of course you MUST check that the IAC motor isn't stuck. The Idle Air Control motor is what adjusts idle for different loads, like turning on the a/c or turning full lock on your steering.

 

[gamefreakgc]

That is what I am starting to think. Can you, or anyone, enlighten me on how the Throttle Body works? Is there a motor on the inside of that that makes adjustments? The reason I ask is I have noticed now that my gas pedal, and hence cable, is clearly slack. The pedal goes about halfway down before grabbing, which corresponds to about an inch of slack on the throttle body.

The accelerator turns it CCW. There is nothing I can see keeping it from turning back CW, even when I try to do it manually. That's why I am wondering about the interior of that component.

Mac

You can tighten the accelerator (gas) cable by loosing the two lock nuts on the cable housing near the throttle body. Then rotate them closer to the end of the cable so it's tighter, but not so tight that it holds the throttle body opening.

Do this for your cruise control and transmission cable if applicable. Slack is not your friend here. All you need is a 12 mm and 14 mm wrench (or a pair of vice grip pliers).

 

[Nelsonmd]

Throttle position sensor possibly?

I second this, mine did something similar when the TPS sensor went out. I woudln't worry too much about exactly what it's doing, they are cheap, like $30 I think and easy to replace. Or you could take yours off and test it with a DMM if you're so inclined. I just replaced mine and never had a problem again, though I only ever had the problem once, so it sounds a bit different than what you have

 

[Weagle2]

CRC Mass Air Flow Sensor Cleaner. Yeah, it's plugged in. Yes, I double-checked because I often do stupid things like that.



Battery is low. I've had quite a few issues with it the last few days. Why would/could that cause this issue? I'm getting good charging voltage, so shouldn't the alternator handle any computer functions once running?

What's the latest on your idle issue?