Ran into some problems with the ol dodger again. to start off I have replaced the Plenum with the Hughes kit. and i have a 02sim from thefastman. I had two snowmobiles on my 4 place trailer that weighs about 1600lbs then the sleds weigh about another 1000 max. So we figure about 2600lbs. I recently put a new trany in it also. I drop 400 miles with the sleds hooked up behind the truck all the way from Bay City MI to Houghton MI. truck ran great and got 12mpg pulling in 3rd.
Got gas in Baraga and didnt make it but another 50 miles to marquett and the truck started running like ****. I mean reallly bad. Would hardly idle, fouled the plugs out bad.
It seems like anytime i put a load on the motor it runs terrible.
Could this be because of a bad cat????

I dont know where else to look

 

Where did you get gas at? A bad load of gas could do that.

 

Yes,the cat can be clogged. Unscrew the precat o2 sensor and see if it runs any better. It also sounds like you may have gotten some bad gas.

 

i would put a couple bottles of Heet in your tank and run some seafoam through it also. Bad gas wil faul out your plugs badly

 

This is the second time it has happened to me. the first time i figured it was bad gas. But the second time it happened i figured it owuld be something else. I get a whooping 5mpg when this happens. It seems to just flood the motor.

 

Not if you got bad gas both times from two different "bad" stations, or from the same station. Stay away from "mom and pop" stations, stick to good name brand stations. Sure, they may be a couple pennies per gallon higher, but they are much more responsible. Shell, BP, Mobil, etc. are good usually. Don't get gas at Walmart or Casey's General Store.

Have an exhaust shop do some tests on your cat. If its bad, they'll figure it out. Don't do a stock replacement if it does turn out to be bad, get a Magnaflow replacement.

Just checking... you do have that O2 sim plugged into the post-cat sensor harness and not the pre-cat, right?

 

Why do you even have the sim to begin with?

 

i have the 02 in the post cat. and i bought the 02 because i was gettin an In-op Cat code. So we figured it would be cheaper to throw the sim on there and hope i wouldnt have any more problems.

Now for you guys who run with out the cat? where are you getting a y-pipe from. I think im gong to just hvae the cat cut out. I know a shop that will probably do it. These cats are retarded because they are the collecter or for down pipes.

I just dont understand why anytime a load is put on the motor it acts up. Truck is running better now. Still not 100% i dont think, but around 85%

 

The cat is no good. When it threw the code for the post cat sensor it did it for a reason, because the cat was no good. All you did with the sim is mask the problem and potentially created some others, like a crack in the valve seat because of the extra heat that is being thrown at it.

 

it is doing such becuase there is a certain amount of air flow through the cat, and when there is a load on the motor, that flow goes up but the cat is restricting it, so it just pressure locks.... and dont take the cat out, just take a peice of rebar and hollow that biotch out, that way if anyone wanted to look under your truck, it still looks like there is one there...

but honestly, i would do it the right way, get a magnaflow hiflow and have it welded in... that way you still have backpressure...

and for god sacks, take the simulator off, that 02 you are " simulating" controls your air fuel mix, and is not good when its not working right...