I had my engine light come on at 70,000 miles I had the oxygen sensors replaced on my 1996 F150 and all was fine. Now at 130,000 it is on again and after having another sensor replaced that was reading 0 milliamps the light is on again after two days. The mechanic said it maybe a clogged fule filter but when replaced the light is back. I am being told know it is the catylatic converter becuase it may have to much flow and giving the sensors an imporoper reading, is there any test before I shell out the big bucks to check exactly what is causing the light to come on. The mechanic did get a code and when looking up the code said it was the converter causing the issue. I have noticed no suggnificant engine perfromance drop. I appreciate any help.

 

Mil elimiators will help this issue I think. If you are having problems behind the cat the mil elimiator will help out and get rid of the check engine light. If the light comes back on, you prob have another problem.


Oh, if you put a mil in your system, don't forget to clear the computer or the check engine may stay on.

 

Thanks for the reply, do the MIL eliminators run me any risk of doing any damage to the vehicle by not handling the problem and would you have an idea where to buy them since it is a new term to me. What exactly does MIL stand for? Thanks again.

 

http://www.mileliminators.com/index.html#information

Here is the site on the MIL eliminators. Really a cool gadget.

 

Try to get the exact code. I think "too much flow" is too vague to accurately solve your problem... The actual code should be very specific.

 

I listed the code in my first reply in the title. I have searched the web and it seems the cats are the problem but I am only going to replace one at a time and try to avoid the huge costs.

P0420

P0420 - Catalyst System Efficiency Below Threshold (Bank 1) Indicates Bank 1 catalyst system efficiency is below the acceptable threshold · Use of leaded fuel · Damaged HO2S · Malfunctioning ECT · High fuel pressure · Damaged exhaust manifold · Damaged catalytic converter · Oil contamination · Cylinder misfiring · Downstream HO2S wires improperly connected · Damaged exhaust system pipe · Damaged muffler/tailpipe assembly · Retarded spark timing § Compare HO2S upstream & downstream switch rate. Under normal closed loop fuel conditions, high efficiency catalysts have oxygen storage which makes the switching frequency of the downstream HO2S quite slow compared to the upstream HO2S. As catalyst efficiency deteriorates, its ability to store oxygen declines and the downstream HO2S signal begins to switch more rapidly approaching the switching rate of the upstream HO2S. Once beyond an acceptable limit the DTC is set.

 

Bad cats it is! (Or at least that's what it appears to be).

If it is cats...
You can get Magnaflow replacement high-flow cats for around 60/each (about the same price as an O2 sensor). If you go this route I'd replace both.

Replacing with factory cats will cost you many times more than the two aftermarket cats. I looked into replacing all of my cats and the Ford units were over $1,000.

 

I took the F150 in to the place I have been taking it for 10 years and they replaced the rear cat. It was replaced with a universal cat. The light was shut off and I was on my way for $168.34 a deal by any means. Last evening the light was back on. I am having the code checked again and going to the next solution. It might be a one by one elimination but if you go to the dealer they change just about everything in one whack apposed to my mechanic doing one thing at a time and saving me some cash. Till next time.

 

I, too have been through the dreaded check engine light. After much investigation and many people telling me what the problems was, I came up with the solution. I went back to AutoZone and had them check the truck one more time. A friend happened to be working there and he said that the code said oxygen sensor, left bank. He stated that it was probably the fuel injector was bad. Another friend told my husband to get a can of Seafoam and run it through the gas. I did this and reset the light by disconnecting the negative battery cable and end of the check engine light. It cost me $5.69 and I run it periodically through the gas, just for good measure. My gas mileage improved, also. Hope this helps.

 

I had the front cat replaced and by luck companies other than ford have discontunied this cat and a universal was availible. My light has been off for 4 days and looking good. If I went to ford the replacment of both cats is over a grand but with my great mechanic the two universal cats and labor was only $369. Hope this helps anyone.

 

I read in a post that someone had the engine light come on when there fuel tank was below half and indicated it was a vacuum line issue. I noticed when I got below half on my rear tank is when the light came on as well. at this point I am only using the front tank to see if the light does not re-appear then if I use the fromt tank and the light comes on I no it is a similar problem and not a head gasket leak. I did put a bottle of fuel injection cleaner in and a bottle of sealant recommended by my mechanic. Time will tell.

 

I am currently attempting to resolve this issue for my truck. I will try the gas cap issue first since it is feasable. I will attempt to find this Seafoam and put it into play. I will follow up and let yall know what if anything worked. Please feel free to post any newer ideas, I eagerly await any help. By the way my dealership service guy said something vague. He stated it had to do with some emission problem?