I have a problem with my check engine light coming on when my fuel gauge goes below 1/2 of a tank. I had the car checked the last time this happened and the garage told me it was the EGR Valve. I just replace the old valve 6 months ago with a new valve after a different garage had told me the check engine light was caused because of a defective egr valve. The 1st EGR valve did not fix the problem so I am not willing to try another valve. Any suggestions?What is oddis the light onlycomes on when the fuel tank goesbelow 1/2 a tank. Someone told me it might be a defective gas cap? Any suggestions?

 

Charlie - I just had the check engine light come on after a full tune up, liquid flush, front/rear diff change, oil change, transfer case, etc. from Goodyear - I took it back twice. Finally the code stuck in the computer and now they say the EGR Valve is bad and needs to be replaced. I get it back tonight (after spending $317 on the valve and $78 in labor).

Hopefully this solves my problem, but after reading this forum, it looks like I could be in for even more problems.

I have a 2002 Rodeo with 100K miles - this was my first tune up/etc.

 

I have 200,000 miles on my truck and it runs great and i get 25 mpg, so i don't worry about the check engine light.

 

So your check engine light is on? Have you ever had the codes checked? Is it the code that says the EGR Valve is out? I was told that if the EGR Valve went bad without replacing that it could kill your oxygen sensor and that is a $1,000+ fix that you need to go to the dealer for. The guy at Goodyear said my EGR was working at 14.1 (I'm not sure what "units" that is in), and now with a new one it is working at 3.1. Optimal levels are 5.2-7 - so it could set off my check engine light again.

So far so good - no check engine light - although I haven't really driven the truck around.

 

To give everyone an update - the Check engine Light is back on.

The guy at Goodyear said that my MAS Airflow Sensor was registering 15 amps - which is higher than the ideal of 5.2-7 amps. He said the code that registered was #300 (ish - I don't remember exactly). So they replaced the EGR valve for $400.

When I picked it up he said that the MAS Airflow Sensor was now running at 3.5 amps - which was below ideal and that could cause the Check Engine Light to go off again - which it has.

I asked him why this wasn't a problem prior to them doing the tune up, etc - he said that when they do a fuel injection cleaning it can sometimes blow carbon through to the MAS Airflow Sensor.

Does this make sense to anyone?

 

I haven't done anything about the Isuzu when it comes to the check engine light , but when it comes to my chevy truck to keep the light from staying on i have to run fuel injector engine cleaner about every 4000 to 6000 miles. If i don't then it does run poorly and the check engine light does come on. My chevy has 160,000 miles on it. I purchased fuel injector cleaner for my Isuzu today but have not put it in as of yet, I just want to see if the light goes out. The Isuzu has 200,000 but it still runs very well except for valve noise. To me, my other Isuzu truck was hard to kill so i don't worry about putting a lot of money in to it. Just keep up with regular maintenance. My chevy 3500 is a money pit. There are specal cleaners for Airflow Sensor but i have heard that to do it correctly it does take really getting in to the system. $400 sounds high and sadly it sounds like who worked on it replaces what was needed insteat of just servicing it.

 

I got taken on the $400 and now am pretty pissed about it. I'm mad because I am using a computer scanner that my buddy lent me, and the MAS Airflow Sensor is still registering 11 amps on a regular basis, so obviously it wasn't the problem.

I continue to get a solid Check Engine Light when I start the truck cold - I used the scanner the last three days and continue to get the P0304 code - which is a misfire in the fourth cylinder. But when I reset the codes, it doesn't come back - so it is only a one time thing when the truck is cold.

The check engine light will blink over 1,500 RPMs but no codes register in the computer - so I assume it is telling me the MAS Airflow Sensor is warning me that it is registering over the ideal 7 amps. I'm not sure if that is a huge problem or not, but honestly it doesn't bother me right now - I just want to get the misfire fixed. Of course this might be bad when I have to get my inspection done in a year or so - but we'll see.

 

What has worked for me is this : Take the air intake tube off, inside there you will se the little sensor on the inside towards the top. Spray it with brake cleaner and scrub with old tooth brush, it will dry quickly. put it all back together and your light most likley will go off. Those sensors get gumed with the oil from the pcv valve and cause it to act crazy which in turn causes light to come on. The light on a rodeo only indicates emissions problems, your vehicle will still run just may reduce the fuel mileage.
Try it and I hope it works out for ya!

 

Thanks - yes, I figured that I would clean off the MAF sensor next. But a buddy told me to try and fix the misfire first, so yesterday I went to Pep Boys and bought a spark plug, some electrical cleaner, and a plug nut for my ratchet. I replaced the plug last night (by myself - which I think is an accomplishment for me, because I know nothing about cars). I let the car cool overnight - started it this morning, and nothing - no Check engine Light - which is really good news.

If it comes back on, I will definitely do the MAF sensor cleaning. Also, I will be checking my gas milage, because I did seem to burn through a tank of gas a heck of a lot quicker last time.