so i bought my truck 2 years ago and it ran fine. about 9 months later the IAC went out and it started surging at cold idle, 500-1500-500-1500 rpm over and over, then it started dieing at normal temp at stop signs and finally threw a code p0123.

so i replaced the IAC with an Standard Motor Products brand from local auto parts. ran fine for about 11 months. then a couple months ago when it gets cold it starts surging again when cold, but idleing ok when warm.

so i stopped by autozone and got their Dura-Last 2 year warranty, heche en mexico, brand and it starts out working fine for a couple of weeks. then it starts surging and dieing.

so i take it back to autozone and swap it for another one. it lasts 1 day and then its cold idleing at 2000 rpm, surging, dieing, throwing codes p0123 and p1281

so now i'm getting tired of changing this damn thing and i don't want another heche en mexico so i return it to autozone for refund and stop at Advance Auto and get a GP brand, made in the usa. so far its working fine.. but its only been 2 hours.

why do these things fail so often ?
and what the heck are they doing inside when they are surging at idle ?

 

The actual motor doesn't fail that often, it's the motor position feed back circuit that usually fails. The problem is very very very cheap quality parts. Even some of the OEM stuff is pretty cheaply made.
Incidentally my truck still had it's original IAC

 

Don't by your parts at autozone if you can avoid it. I'm not trying to slander anyone but I've never had any luck with the **** I get from that store.

Advanced - no problems
napa - no problems
auto supermarket - no problems

 

Idk, I only buy from premium parts stores and Iv gone through 3 myself....thats the one thing that pisses me off about this truck.

 

Just a thought, but many years ago, in a land far away...
..no
anyway, I had a problem with ignition parts in a distributor being faulty. After 3 attempts with "new" parts...no good results.
Then while in a state away from home I bought a set of points for it and, lo, never a problem again!
Turns out that Sorenson had some bad points out there (which they never did recall) But!...if you brought them back you could get them replaced...if you dare. Just a thought, but try getting one ordered, say, on-line from another "zone" (not Auto) say, out of the Southeast, and see if that solves the problem. (i.e. different lot number). This also happened in my business once with light S/O light bulbs that lasted <100 hours. However, these were eventually recalled by GE!
WC

 

idk either. the SMP was a premium brand and it only lasted less than a year and had little/no warranty. it came from the premium parts store with machine shop thats only open M-F 8-5 and you better know what your doing cause they're not much help and pretty arrogant to boot.

by contrast, the autozone is close to the house, open 7 days a week, 7am-10pm, the kids in there really try to help you, the prices are low, the warranties are long, they loan you expensive tools for free (deposit required). the only problem is that the autozone brand is pretty cheap and sometimes you get crappy parts. Advance and Napa have a little better name brand of parts, but there aren't any here close to the house. this was the first time i ever got two bad parts in a row, and it probably is caused by a 'bad batch'. that's why i drove across town today to just get 'something different'.

i appreciate rabbler's explanation about the feedback circuit. it does seem like when these things fail that the pcm is sort of randomly giving it in/out commands because it doesn't know what the silly thing is really doing. this is also why i've said that it doesn't do any good to 'clean' these things, because the problem is not gunk or sticky, its just electronically fouled up and no amount of cleaning it is going to do any good.

 

Yeah, the electronics seem to be the bad guy on these devices. That's where a good scanner comes into play. You can check on exactly the operating perameters of the part in question. But, then again, that only reaffirms what we already know...that the damn things are messed up...NOT where to get a GOOD quality one.

 

Did u say you got the iac from napa, because thats where i keep buying mine

 

i got an SMP brand from napa. lasted 10 months. little/no warranty.
i got 2 autozone Dura-Last. one lasted 2 weeks. one lasted 1 day. 2 yr warranty.
i got a GP Sorenson from Advance today. ok so far, we'll see. 1 yr warranty.

 

Brand name means so little these days. Some of the reputable brands from years ago are still around but now they have been bought and sold so many times and the manufacturing is outsourced to the 3rd world or the lowest bidder.
It's a wonder anything works at all.
I remember when Timken, Bendix, Wagner, Moog andFram meant TOP QUALITY! Sadly that isn't the case anymore...