I had the cats cut off my 95 F150 4x4 5.8L and now it idels to fast, shift is really stiff and check engin light is on. is this a back pressure issue or somthing else. Somebody please help

 

I know the computer takes a reading before and/or after the cats. If the sensor is gone or fouled the check eng light comes on. That will also cause the engine to act the way it does.

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1997 XLT Teal 4.6L Flareside 4x4 ORP. Automatic, Reg. cab, 3.55LS, tinted windows, bug deflector, Dual exhaust, K&N Generation 2 air filter, BullDog keyless entry/remote start(installed myself), Modern 16" wheels, bedliner, Covercraft tonneau cover, White faced gauges, electronic shift on the fly, Clarion ADX5655z Double Din Cassette & CD, 4 Pioneer TS-A6865 speakers and superchip. Going to add headers.

 

It's also against the law to cut the cats off.

 

It is essential that you make or buy o2 sensor sims they trick your engine int o the correct code, so in theory the computer thinks that your cats are still there with out the cats you o2 sensors are not feeding the computer the info it needs so it is compensating by enriching the fuel mixture, I think, so it is running higher to burn off the excess fuel. Ask MAx Mitchell he know s his stuff, Im just telling you what I know, but like him I have driven my truck, or a vehicle with obdII with out cats it runs like crap. Max if I was incorrect about your experiences with no cats I am sorry. but I was just sharing your knowledge.