Hello my cheyenne 97 idle rough and accelerate poorly. At idle it sound like it as a cam in it.

[vanec]

Hello my cheyenne 97 idle rough and accelerate poorly. At idle it sound like it as a cam in it. I had the truck for a while so over the time I changed a lot of things. Maybe someone of you ran into this problem. I think it's related to a fuel issue since I only have 53 psi so I changed the fuel pump but I now I have 55psi but still act the same maybe it's juste my gadge since it's a cheap one from amazon. Injector spider assembly was changed also new regulator. Every thing related to ignition is brand new so I really don't know what it could be. Stock it's recommended 60 65psi but again I don't know if it's because I need a specific brand fuel pump for that truck or my pressure gadge give me a value that's under reality

thanks for the help

 

[bo1998gmck1500]

Could just simply be a clogged fuel filter, I’m having a similar problem. Ive changed spider injectors distributor, wires, plugs and it sounds like I have a cam and when I put it in gear it tries to die.

 

[Schurkey]

Download the service manual set for your vehicle from the links in the Sticky thread section of the Engine forum.

Follow the fuel pump diagnostic procedure, which is going to include clamping-off various parts of the fuel plumbing and reading the resulting pressure.

Make sure your fuel pressure gauge can be trusted.

Connect a scan tool, verify EVERY sensor and computer output. Double-check the EGR system. Look at the misfire counts for each cylinder, see if you have a specific problem child. Verify fuel trims at idle or whenever the engine runs rough.

How old are the O2 sensors?

 

[Chevyman1969]

I would go to O'Reilly and have it scanned.

 

[Schurkey]

I would go to O'Reilly and have it scanned.

I've never seen them scan a vehicle.

I've had them read codes when I've been out-of-town and away from my scan tool. The most-recent time, their device could only read generic codes--P0300 "random misfire" in that case, instead of the actual P0301 "cylinder 1 misfire" which would have earned them a sale of a replacement ignition coil for my Trailblazer.

In short...they're almost but not quite useless.

 

[docstoy]

Having good information is key to being able to figure out problems with your vehicle, oe manuals do this because they give key information for service technicians fixing there vehicles. OEM don't like paying techs for swag repair and techs don't like to work on comebacks, you don't make money on comebacks . Having reliable tools and diagnostic equipment is also key in repairs , if you don't trust your equipment then your just second guessing yourself. If you have a tool your not sure about, such as a fuel pressure gauge, if you know someone that has one compare it to their tool, if while using does your tool and their tool repeat same reading multiple times ? If comparing always try to verify on good known vehicle, if your tool differs from theirs but repeats itself multiple times with same reading then could be calibration of tool or needle bent or moved ( fuel pressure gauge ) if not you trust your tool then add or subtract difference so you will have fairly accurate reading of what your cking or testing . And use service information you can trust (OEM) is always best unless your using aftermarket products that use or have their own procedures . Scan tools make diagnosis easier and quicker but alot of times you can use a DVM to look at voltage/resistance if that's all you have it just takes longer and you should verify voltage and ground with DVM everytime before cking or testing or results could be skewed . Sorry for long post but just trying to show why a lot of very good forum members stress using tools and service information available on this forum.