I hate the SES light!!!

[jnicks01]

I've been dumping money into my 99 about every week to keep her running smooth instead of spending the cash on a new car payment. It has been running great, but all the sudden, my SES light came on again. It happened as soon as I drove about 200 miles and fueled up. Gas cap is on tight. I've noticed the fuel pump is whining a bit more than usual. I replaced it about 4-5 years ago. It still seems to be running same as before the trip, except the idle is a tad rougher than before. Could my fuel pump be going out again? Would it be trying a new fuel filter? I know the light means about 1000 different things, but thought a little insight could help until I can get it checked out.

 

[T-Bagg]

I've got a '98 with some what of a rough idle and an SES light. My light is for a MAF sensor and Cam Shaft position sensor. About $400 for those.
The easiest way to find out what it's for is to do what I did, find a friend with one of those hand held diagnostic computers. Plug it in under the dash, get your codes, then Google that ****. Or once you get the codes, a Haynes manual will have a list of fault codes and associated malfunction. I've also been told Auto Zone will run a diagnosis for free.

 

[shreksbrother]

Autozone, O'Reillys, Advance Auto, any of those chain parts places will hook you up with a free check of your trouble code. Definitely worthwhile for the price, as it'll give you a better idea of what's going on.

 

[jnicks01]

I just took my MAF off and cleaned it about 2 weeks ago. I will recheck that first. If not, Autozone...here I come. Thanks for letting me know that they do free tests.

 

[Mike97]

I just took my MAF off and cleaned it about 2 weeks ago. I will recheck that first. If not, Autozone...here I come. Thanks for letting me know that they do free tests.

What method did you use to clean the MAF? I've heard of people damaging them by trying to clean the MAF. They are very delicate inside, and easily damaged.

 

[treepete]

real gentle with MAF cleaner ( or electronics cleaner) and a Q-tip.

 

[T-Bagg]

I also cleaned my MAF sensor in an attempt to get rid of that code. Which lead to me cleaning the entire intake from filter through throttle body. With MAF sensor cleaner and throttle body cleaner. Still didn't git rid of that code. Some one tried to tell me it was because I had a K&N air filter. Don't listen to any one who says this, they're effing retarded.

 

[Mike97]

There have been cases where people have cleaned their k&n filters and over-oiled them. Then the excess oil is sucked out of the filter and coats the MAF. I have read where this has caused problems. But you would really have to dump an excess amount on there for that to happen I would think. However, a k&n filter, or any high flow filter for that matter, will not cause the ecu to throw a code.

 

[jnicks01]

When I cleaned it, I used MAF cleaner and never touched the filaments. Spray took everything off without using q-tip. Cleaned all connections and put it back together. I took it off again last night and everything is in tact and clean. Sprayed it again for good measure, but no change. Air filter is pretty new too.

I'm thinking of running a can of seafoam through it to see if that will clean up the idle a bit. I also just ordered a handheld code reader this morning. Figured it was a wise investment. I'm sure I'll have many more codes pop up in the future (or be the guy with one so my friends can come over and use it). I'll let you know what it says after I receive it.

Any other simple fix ideas are still welcome until I can get the code.

You guys ROCK!!

 

[blk87brd]

Had a similar problem with a 99 Tahoe. SES light came on, idle went to hell, sluggish coming away from lights etc. It was the EGR valve. I'm told they can be serviced however, I have never done one. You will be happy with your code reader. It's a useful excercese to take the reading then take the vehcile to several shops. It really helps establish the honesty of the mechanic. I have done that when I have had problems away from home. Anything that occurs near home, I will fix myself, but occasionally you find yourself without that option.

 

[jnicks01]

Well, I love my new code reader, but it has given me a P0420 code (catalyst below efficiency bank one). The code is a pending code too. After some brief research, I'm guessing that it is my cat converter. Anyone else aware of this code? From what i've read, the downstream o2 sensor could be malfunctioning, but most likely not. I'd hate to have to do the cat, but if that is what has been delt to me, then so be it. OH, and what is bank 1 mean?