Some may recall my other post, long story short, I tuned up the truck with all new parts, set timing. Helped immensely with acceleration, and MPG.

83' with 302, new REMAN Motorcraft 2150 installed by PO.

So this flat acceleration has appeared, it's seems to come and go. The MPG is still about the same, it's just the performance has changed. Last I checked timing, to see if it slipped, it was still set, but I did notice it drifts a little with the light.

It use to kick down with mild pedal pressure, but that seems to come an go. Only with a heavy pedal pressure does it kickdown, but then it feels flat with not as much responsiveness that it did have. So I feel confident it's either a fuel or fire issue.

I am thinking the distributor gear is getting sloppy. Now that the cold weather is out, the carb could use a tune for the higher temps. I have not touched it since I purchased.

Overall, the truck runs good, but this flatness is driving me crazy as I had it performing pretty good. Need some suggestions, sounding board.


UPDATE: Removed the CAT replaced with straight pipe for now until I can build scavenging system. Helped a good bit, but still pretty flat. Odd the tune changed over night just like that, one reason I suspected the CAT being plugged first.

So, I will clean with Seafoam spray the Motorcraft 2150 a few treatments, and in tank. Tune the carb, see if that helps. Will run vacuum gauge test. '

Any other suggestions?

 

How many miles on the engine? Drifting timing could be to due to worn timing chain and gears. Newer Fords run crank trigger via EDIS which eliminates this possibility. It's also retrofittable to older Fords. I would imagine that the issue is either a vacuum leak, flat spot in the fuel curve in the carb, or retarded ignition timing caused by timing chain wear, distributor issues, etc.

 

85K, but, I just sold it about 15 mins ago. Loved it, but about to move, all my tools are where I will be moving to, no time or storage to get it dialed in.

I appreciate all the feedback. It went to a good home, the buyer is happy, I will miss it, but I've had 30 vehicles since I started driving. And I've learned there will always be more. I am certain y'all will see me back in the future.

Have a great weekend.