Miata bogging in gear

[ninesixtbird]

Same question i posted on Miata.net

Today my car has been acting weird. When I was accelerating in the car, it would barely pull in 3rd gear. The clutch, pressure plate, throw out bearing, pilot bearing was all replaced about 8000 miles ago. I've own the car for about 5 years and I have always got a noise during deceleration.

The car is sometime feeling like it's trying to pull off in the wrong gear, like trying take off going 20mph in 5th gear when I really in the correct gear.

When it's bogging like this I press the clutch in and see if the engine will rev freely with no issue. So i'm thinking the issues lies in the drive train.

Its pretty consistent now.

I have a spare diff and driveshaft, but before I try swapping things around I wanted to get some input. When I did the clutch replacement I torque all the bolts to specs, even some time after, I put my car on lifts to check it out before this problem.

[iscariot]

Which year? My initial thought(s) are AFM or MAF need cleaning, and when you free rev it unsticks the AFM / clears the MAF momentarily.

[iscariot]

On the noise front - does your rearview mirror shake at 60mph? I'd inspect the driveshaft Ujoint for slop.

[ninesixtbird]

Rearview mirror doesn't shake, on startup I did get a noise that sounded like it could be the ujoint, it sounds like something bending and straightening back up hard if that makes any sense, doesn't seem to happen lately. When I freerev it doesn't stop the car from bogging. The bogging is random but it is a high consistency.

[iscariot]

Wondering if your ppf is loose. Still think the bog is fuel related though, maybe a pump.

[ninesixtbird]

I'll check the ppf, I have a spare 1.8 diff and driveshaft I've been holding onto for a few years. Just need to get some 1 piece half shafts. I held onto it after reading about 1.6 diff blowing up, unfortunately when I got it at the junkyard someone already took the half shafts.

[ninesixtbird]

Ending up being a problem with a fuel injector on cylinder #1. Problem fixed. I really thought it was a drivetrain issue, since I could rev with no issue(actually revs better now), but later on Sunday my car started to misfire so it made it clear it was not that.