duracel831

Alright so lets start at the beginning, always a good place. About 6 months ago I bought subs, and amp for my 1999 Lexus ES300. Had them installed and running off stock Lexus radio/CD player. No problems. About 3 months ago I started getting a CEL P0171. When light came on the car, almost instantly started to have a rough idle and I could smell exhaust a lot more. When I would take out the fuse for the Fuel Injector (FIL? fuse) and put back in, the problem went away. The light would come back on after about 2 or 3 days and I would have to repeat. So I started doing research. It is a lean code. Could be anything from dirty MAF which i cleaned, exhaust leak, problem with fuel injectors, O2 sensor, etc. Well the light hasnt come on for about 2 weeks. About 2 months ago I installed an aftermarket deck for my car, a Pioneer and as of yesterday when I would drive with my stereo on and headlights on, the cars dash lights for seatbelt being unbuckled and car door being open, and clock in center of car were flickering. I bought a brand new battery for the car about a month ago. Decided today to buy a new alternator, it was time. Installed it fine, thought that might be the issue, turns out even after new battery and alternator, if I have both my stereo and headlights switched on, my interior lights flicker and also the car hiccups when I put on the gas. If I turn the headlights off, the stalling goes away instantly and the CEL has not come on at all. Almost feels like its stalling for a second then catches up. It is not getting enough gas. So I am assuming that the issues with CEL and rough idle and exhaust smell (which started after installed new audio setup), and now the electrical issues with flickering lights and the stalling or hiccuping are related. Is it purely electrical because I am drawing 100x more power then the car was intended for, (which is weird because I have brand new battery and alternator) or do you think there is also an issue with a gas/air ratio, i.e. exhaust leak, O2 sensor malfuction, fuel injectors need to be replaced. I know all of these things are related and want to fix it. I would greatly appreciate any feedback. Thank you. P.S. After installing alternator today, I noticed a tremendous increase in sound quality from subs and stereo.

duracel831

Just a heads up, the car is a 1999 with 140,000 miles on it.

mmatheny

Does the flickering change intensity with the stereo volume??

duracel831

No, the flickering remains constant whether I increase or decrease the volume

tony2000LE

My 2000 ES was doing the same thing with the rough idle and exhaust smell. Start with replacing the MAF sensor, and reset the CEL. It's most likely the cause of the P0171 code. I also tried cleaning my MAF sensor first, and it turned out to be the problem. 97% of the time, it is this sensor that causes the rough idle, and the code. T

duracel831

Cool thank you so much. I have been thinking a lot lately about replacing the MAF sensor. Kind of going down a checklist of possible problems but not wanting to be one of those people who just blow tons of money and fix everything that it could be. Thanks again

Hayk

iTrader: (1)

These cars are known to have flickering issues even with stock parts. You may have overloaded your electrical system with the new components. The stock alternator is only 90amps which is fairly low.

duracel831

I was told as well that I might want to consider getting a capacitor.

mmatheny

A capacitor only filters out AC hum from the alternator that leaks into the stereo components. Not sure how that would help your issue.

duracel831

I ended up getting an installing a new alternator with my brother and also just replaced my MAF sensor. It has been at least 2 weeks since the CEL light has come on so Im hoping that was the problem. Thank you all for your help. If anyone still has any ideas or suggestions please let me know. Thank you