truck started to run rough....

[Sworn]

Any advice would be helpful! My 88 4X4 has 132k on it and WAS running great! The trucks has new: plugs, wires, cap, rotor, ignition coil, ignition module, fuel filter, new exhaust no cat with a flowmaster muffler. Yesterday it started to run rough....The exhaust note totally changed as well. I took it to my local muffler shop and had them double check the exhaust, no leaks. Any idea's or places to start looking. I want to check it for codes but I have no idea where the diagnostic port is. I was told that it's on the passenger side by the fuses but I still can't find it. Any help would be appreciated. Thanks

 

[Sworn]

Forgot to mention, new battery and alternator.

 

[baddis]

tech library start here. this will tell you how to pull the codes from your truck

 

[Sworn]

I tend to think the truck likes a little more back pressure than it has now with the Flowmaster and no cat.........

 

[Sworn]

Maybe I'm an blind but I still can't find the port to see if I have any codes.........

 

[holyford86]

its red and it has a house shape to it. It will be down next to the airbox, you might have to move some stuff around to find it.

 

[Sworn]

its red and it has a house shape to it. It will be down next to the airbox, you might have to move some stuff around to find it.

Thnx

 

[chris1]

I have a 87 2.9 and found mine exactly where holyford 86 said it is. Mine was right between the blower fan housing and the airfilter housing on the right front fendor well. Two wires. Both plug into the tester. One is red and I believe the other is a tan or off brown color. The bigger red one does resemble a house. Hope this helps.