A fuel pump and it's fuel pressure isn't sensored. That could account for your problem without creating a code.
Hey peeps, I'm new here. I have had some car trouble and figured this would be the best place to ask, since my dealership "can't replicate the problem" . So here goes
I drive a 2012 3.7l Ford mustang , it has about 99k miles on it. I'm having some RPM drops when accelerating. I doesn't happen when I floor it from a standstill. It only happens when I floor it once it's in second gear and the RPM drops at around 4000rpm , it drops by about 200rpm and then continues to accelerate fine.
This also happens when accelerating normally ,in 3rd gear at around 2200 rpm.
This effect is more noticeable after a cold start. Once it warms up instead of dropping a couple hundred rpm it (tachometer needle) freezes at 4000rpm and then moves up normally but it is still noticeable in 3rd gear . This is very annoying .
Yesterday I took it to the ford dealership and they charged me 95$ to run engine diagnostics with OBD just to tell me there are no error codes and hence nothing wrong with my car. When I asked the technician to come along with me for a drive (by then it was hot outside and the engine already warm from testing ) the effect wasn't as pronounced and the technician told me it's the torque converter locking up and that's why the RPM surges and that it's for efficiency . Doesn't sound right to me.