Ok, I think I broke it for sure now


Hello, recently I posted about my issues with the fuel induction service I had at WalMart and the loss of 6 mpg. I had all sorts of good suggestions. My MAF was tested at the Garage and it was reading at the very top range of the allowed specs. I had it read by another garage and they confirmed the high reading.

Another suggestion I had was to clean the Throttle Body, which I did this past weekend. When I got to the TB, the carbon was so bad around the flap, and the body wall, that the flap did not appear to opperate correctly, like it was not able to close. I cleaned it throughly, some with the vehicle running, and some without it running. When I put the air flow parts back on, which was basically a plastic housinge that took the air from the filter past the MAF, to the TB, The truck ran terrible. I let it idle for a bit, and the Idle was very high, and when I would rev it it would stay at the top of the rev, like it was stuck. Also the check engine light was on.

I went to the local auto parts store, had them check the code, and they said it was the MAF or some other sensor, that my truck would have one or the other, and that it was having low voltage. They cleared it out, and the light stayed out for a day or so. Last night, it came back. I am going to get another check to see if its the same problem, but I know it will come back.

Now, I dont understand how cleaning the TB could have tripped the MAF, I went no where near it. Could I have messed up something spraying the TB Cleaner into the TB?

Also, my mileage still is in the tank. No change! DANG NABIT, that is the problem I have is I can’t just let this go. The vehicle is not running right! I am to the point where I am ready to trade the truck that I love in, because I can’t figure this out.

I stated before, if someone can help me solve this, I will send them a box of cigars or their favorite beverage! HELP.


I think the MAF sensor finally took a dump. When it was read before, it was on the high end of OK. Now, the CEL is telling you the MAF has problems. Get it re-tested now that the CEL light is on. I’ll bet it has now failed.


Howdy consider adding a can of Sea Foam to gas 8 gallions in tank an see if its great cleaning ability helps your situation.


Disconnect, and reconnect the MAF electrical connector. Check hoses which attach to the intake tube. Ensure that the intake tube is sealing at both ends. Check that the throttle plate is closing completely. You can usually determine this by checking the stop on the outside. A bad, or missing, pcv valve can allow too much (unmeasured) air into the engine. You can use a vacuum guage to tell if there is any vacuum leak. The instructions are in any Haynes, or Chilton’s, Repair Manual.
A misreading engine coolant temperature sensor can cause the engine to run too rich, It can even prevent the engine control system (computer) from going into controlling mode (closed loop). It WON’T set a code.
Antifreeze is poison to an oxygen sensor. It might recover.


You know the saying- you are what you eat? It applies to your engine as well. You have to be careful about what kinds of solvents you use because some can kill your O2 sensors. Make sure it’s O2 safe.

There used to be some TBs that were coated and if you cleaned off that coating by abrasion or solvents, it would spell trouble down the road. Not sure if they are used anymore but the point is, it pays to find stuff like that out before doing a cleaning rather than on the backside of the “repair”.

The next question is, are you sure the throttle plate isn’t still sticking? You said it seemed like it might be so that’s the first thing I would check.


The cleaner was specific to TB, it was not a normal engine cleaner, so I hope that is not it. I know it did not appear to be closing the whole way when I had the things apart. should it be stright up and down? making a 90 degree seal in the housing? It was not at first because of all of the carbon, and when the engine was running I could not move the flap with my fingers to clean it like the instructions said. but when it was not running I could push it, it was a bit off of being straight up and down.

My o2 sensor is not in the area of the TB as I can tell from my schematic, but it would not be the first time I read that wrong. I will double check.


Both end are with two double clamps and a hard plastic housing, I think I got it back on right, but I will certainly double check. The throttle plate stop? How would I check that, and I asked this below, but should it be completely up and down in the housing? It was not, it was cocked a bit and i have no idea why or how that happened.

Where can I get a vacuum gauge? Auto Zone? I think this is my problem all along, but the garage, since I did not have my original service there (though they are not the best anyway, had an alignment and they tore up my rims, but I digress) will not assist me in any way with this problem unless I pay full price for all of the tests, which run about 90 bucks a pop. If I can check the vacuum leak on my own that would be great.


O2 sensors are in the exhaust pipe, before and after the converter. Whatever passes through the intake will go through the exhaust without a passport.