They usually don't go bad. The MAF may need cleaning.

But the MAF if bad will cause either a rich or lean running engine depending on how it goes bad and the TPS will usually cause a fast idle if it goes bad.

 

I'll check the Ford troubleshooting disc on this for you later next week (PC is down now) to check the specific symptoms, but needless to say that the car would have terrible gas milage and would run VERY badly. I would just clean the MAF first though. There is a thread here which talks about how to properly do it.

 

That's good.....the gas mileage hasn't changed in the last two years. so I'm assuming they are both ok. I was just wondering if that was a 'preventive maintenance' item that should be replaced, or whether I should just let it go bad before replacing.

I'll check the post on cleaning the MAF -- I've done that on a friend's Ford truck, so it shouldn't be to difficult to follow.

Thanks,
David

 

I was just wondering if that was a 'preventive maintenance' item that should be replaced[/b]

As far as the MAF goes yes, but not replaced, just cleaned. There is special cleaner just for MAFs. Use it instead of an 'electrical' cleaner.

 

MAF sensors can go bad - i don't know why people say they don't, but i've changed many over that years that even cleaning wouldn't help. That being said, follow everyone's suggestion and clean it first, and reclean it once a year or so. I do mine twice a year - every spring when i put my CAI on, and every fall when i put the stock airbox back on. A dirty or failing MAF usually makes the car run lean, and the most easily recognizable symptom of it is ping under load. Vulcans are bad for it, even with a good MAF. The 'tec doesn't seem to ping as much, unless the MAF isn't reading properly.

As for the TPS, they too can fail, tho not as often as MAFs, and there really isn't anything you can do with them. When they fail, replace them. You'll usually get a code for a bad TPS, and/or you may experience a dead spot in the throttle, sluggish acceleration, poor idling and a few other things.

 

I do mine twice a year[/b]

Yep, same here We consider it part of regular maintenance.

 

I also have a question regaurding the TPS. Now that my MAF is nice 'n' clean, the engine doesn't spew out codes. My idle problems remain though, for example at 1 stop light, it will idle @ 800 rpm, then at the next stop I basically have to stand on the brakes to hold the car, in Drive the tach shows 1200 rpm, but if I go to neutral, it shoots to about 4000 till I kill the ignition. Restart the idle is normal again. Bad TPS? No codes are thrown. BTW, how does one "grease the cables" properly? ( I want to rule that possability out, but by hand everything feels good, no sticking)

 

You can test the TPS with a volt meter. With the ignition on and engine off back probe the connector. At closed throttle you should have near 1V. Slowly open and close the throttle and watch for a smooth rise and fall in voltage. Any sudden jumps will indicate a bad TPS. This could also be a wiring issue too.

The IAC would have to be monitored in real time. To really see what is going on with it you need to see if it is being told to be higher than normal or just sticking. If it is the original one and clean it did not help probably time to replace it. But I would look at the TPS first as iot is easier to check and cheaper to replace.

 

Does anyone know if the IAC is only used during idle conditions (as would be true to its' name "idle air control" ? Or is the IAC also used during driving conditions... That is, does the PCM use it for only idle ?

:x:

 

The IAC is used 100% of the time to varying degrees.

 

My MAF got dirty or something on it from sitting 2 weeks. Car ran kinda funky and I cleaned it quick in the school parking lot and it ran better.