Engine running rough on acceleration (chirp/shudder)
 

Hey guys. Looking for some help with a diagnosis here.

My 1964 F100 Styleside with 292 y-block just started running "rough" all of a sudden. For the last 5 months, she has been running smooth and strong. The carb was rebuilt in November.

Here are the symptoms now . . . Friday morning, truck ran great. Friday afternoon (after warming up the engine), I started to get a chirping/shudder on acceleration. Sounds terrible and makes this noise while accelerating in any gear. Doesn't make the noise (or at least not very noticeable) when I rev it while parked.

I pulled all the plugs on Friday (a couple were rather loose) and checked their condition/gaps. All looked similar and were in good shape. Drove it for a test run, and it still sounded rough. Had a busy weekend (with my one month old) and didnt get to address it anymore. This morning, it drove fine for the first 15 minutes, and then the sound/shake kicked in again.

I am not sure what to check first here. I am handy around a truck, but I am by no means a master mechanic. Any advice would be greatly appreciated.

Like I said, this truck ran like a dream until Friday, and now when I accelerate, I get a noticeable shimmy and the engine has a chirp/roughness. Seems to me like something with the mixture, but I dont know enough to just know this.

Thanks guys . . . appreciate your expertise! Please feel free to ask questions!

vacumn leak? but to me those sounds shudder chirp is clutch an back drive line

Thanks for the ideas . . . truck ran terrible on the way home from work today. Shuddered so bad that I didn't want to accelerate. Ended up getting her home below speed limit and rough.

Once home, I revved it a bit, and I think you may be right, schoo. The chirp appears to be coming from the rear differential area. Not sure what the problem is though.

The enging also sounds rough when i open the throttle and I had one small backfire. Tomorrow morning, I am gonna check out the differential and also inspect the fuel filter. Maybe I should look at the distributor too.

Any other ideas?? Any advice?? Thoughts?

Thanks guys . . . this is bugging me!

Maybe an issue with the carburetor accelerator pump? This is easy to check and replace if necessary. No idea about the chirp...