I have a 96 3.5L 24 valve Intrepid. I have 139K on it and was hoping to get another 70K on it. I also just moved to a block away from work and drive it on the weekends about 120 miles round trip. I NEVER put anything lower than 89 octane in it.

I am not a car mechanic I am a PC mechanic.

Where I used to live the mechanic that I had been taking the car to for years replaced the EGR valve in January. Then the thing started to overheat consistantly. That resulted in a valve and head job at the beginning of Feb. I was laid off work on March 1 so didnt drive the car much till I started working again on the 10th April but on the way to that interview the check engine light came on. I took it back to my mechanic who said the EGR was dirty and thusly cleaned it. A day after starting my new job the check engine light came on. Two fuel injectors were replaced. The rest were supposedly cleaned. At that time I was taking the metrolink and also switching driving time with my other car. The Intrepid I would drive to and from the metrolink on some days and on the weekend about 20 miles.

A few weeks after starting work here the check engine light comes on again. I stop at a mechanic that is a few blocks from me. He looks at his computer and says one of the cylinders is misfiring and that could be simply a tune-up. He cleared the light. He had asked if I had any work done on it and I told him of the two fuel injectors he stated that it could simply be that as well and if the light comes back on to stop by. When the light did come back on it was near my then home so I took it to my usual mechanic who stated the EGR was clogged. A week later the light came on again but this time I took it to a different mechanic who said that a hose was loose (from the previous ERG work) and I got the fuel filter replaced. Then a week or little more later the light came on again. This time I took it to a mechanic where I live now. He said a cylinder was misfiring and thusly I got a basic tuneup to include wire harness, fuel and air filter replacements. The check engine light came on AGAIN last week so I took it back to this newer mechanic who said that 6 codes came up to include the catalytic converter. He asked what kind of gas I was using. The night it went on I had just filled up with Chevron 89. He cleared it and was driving it for a few days but nothing came up. I then did my normal weekend trip and on the way back the light came on again. I took it back to him this last Tuesday and he was saying the EGR was dirty. He cleaned the throttle bodies and a few other things.

I know a long story but to me needed info. My question is: What could be causing this EGR to get dirty so fast? I make sure I give my gas cap several twists to make sure it is on tight and has a seal. I am thinking of going to 91 octane as I am not sure if these gas stations are dorking with their gas and mixing them with cheaper lower octane gas. I put in those gas boosters.

I do still like this car. The Intrepid is fast. It has power. There is a monster under that hood but I can't keep getting nickel and dimed every 150 miles of driving.

 

My mistake: It is EGR valve. exhaust gas recirculation valve.

Does no one else have a problem with this? I have done some searches on this site and came up nada so today I decided to do a search on google. If I find anything that is specific to the Intrepid then I will link that here.

 

My EGR valve used to stick open on (can't remember if it was warm/cold) days. I scanned it, the code came back to EGR problems. I suffered no loss of mileage or any obvious signs. I didn't do anything about it (not advocating this). I had 199,723 miles on when the engine lost its bearings, put at least 50 K on with that bad valve. If you have obvious problems, I'd get it replaced. Sorry I can't be more help.

Red

 

As you probably know by now, the EGR pumps a bit of exhaust gas into the intake manifold at certain times. (Thus the computer controlled vacuum system to open/close it.) It's there because modern cars run very lean. IIUC, exhaust gas helps dampen the combustion cycle. (If it burns too hot, you get a lot of NOX output, which can cause the car to fail inspection.) If it sticks open, you won't be getting full performance, if closed the engine's more likely to ping.

I'm glad you mentioned the 2 cylinders that weren't firing correctly. It's usually a too-heavy amount of carbon in the exhaust that then gets into the valve, fittings and its hoses. (Obviously these all need to be cleaned and/or replaced. The fitting may only have a 1/16th" hole... and it's sometimes not cleaned.) Any way, anything that causes excessive carbon in the exhaust will cause a quick buildup of carbon. This can be a bad O2 sensor, misfiring cylinders, or even excessive oil burning. I once heard this could be antifreeze getting into the combustion chamber.

Even at that, this unit should stay clean enough for weeks or months unless the condition is severe enough to feel when driving. You might see if they have "sniffed" the exhaust with a sensor. Those supposedly can tell if it's oil, gas, and/or antifreeze, or how much "off" the car is in its desired emissions. Diagnosing what's causing this will at least be narrowed down.

(I'm just another driver who's had similar probs w/ the EGR valve.)