[Kenobi13]

Hey guys so I recently got my car tuned and modded. I got p1sc procharger full kit, lt4 high pressure fuel pump. msd intake manifold,103 throttle body, kooks long tube headers with off road connection pipes and gt haus valvtronic exhaust. Also got catch can and msd spark plugs and custom tune. So my tuner was doing dyno on mustang dyno and he said it made around 540-550whp which is like 620whp on dyno jet. But I don't think the numbers can be that different from each other? Also I noticed my transmission started lagging around 5-6RPM or it gears up too early or too late that I get like 1 second delay.
Also I was recently pushing the gas and then I started braking so car automatically started gearing down and it started the pop and bang exhaust shooting and I got the engine light flashing for like 10 second while i was on red light and then I start driving and it got away. I check in GM it was saying this.

Flashing check engine light is the misfire notification. If it starts and goes away then it is a random misfire, if it continues and wont go away then stop driving.
Also it said that you get this notification when the fuel is being dumped in to the exhaust system and it can cause some big problems.

So did anybody got engine light flashing for 10 seconds and what was the issue?
Also what you guys think about the 550whp on mustang dyno? Is it really 620whp on dyno jet ?

Thank you for your attention.

[ST1LE]

Dyno numbers are for comparison only, what were your base HP numbers? Looking at the delta change after mods is all that number is good for. Dynos can be calibrated, so you cant take a number from one random dyno and assume that equals something else on a completely different machine.

A drag strip will better tell you the power you're making, trap speed for example is a good indicator.

[1LE801]

I would take it to another tuner immediately. That or I would get a scanner and start logging and working with a reputable tuner. I use Ricki Fast and he absolutely transformed the way my car ran. ESPECIALLY my trans. Getting the trans right was the single biggest improvement we made on my car through the 3.5 years of having it built.

A flashing check engine light is not a matter to be taken lightly as i'm sure you are aware. I'd run different plugs also but thats just me......

[SomeGeoffGuy]

It will start misfiring like that when you get a bunch of spark knock and the PCM pulls a bunch of timing. Be careful!

-Geoff

[Kenobi13]

Originally Posted by ST1LE

Dyno numbers are for comparison only, what were your base HP numbers? Looking at the delta change after mods is all that number is good for. Dynos can be calibrated, so you cant take a number from one random dyno and assume that equals something else on a completely different machine.

A drag strip will better tell you the power you're making, trap speed for example is a good indicator.

Got it thank you

[Kenobi13]

Originally Posted by 1LE801

I would take it to another tuner immediately. That or I would get a scanner and start logging and working with a reputable tuner. I use Ricki Fast and he absolutely transformed the way my car ran. ESPECIALLY my trans. Getting the trans right was the single biggest improvement we made on my car through the 3.5 years of having it built.

A flashing check engine light is not a matter to be taken lightly as i'm sure you are aware. I'd run different plugs also but thats just me......

Yea I should do that thank you

[Kenobi13]

Originally Posted by SomeGeoffGuy

It will start misfiring like that when you get a bunch of spark knock and the PCM pulls a bunch of timing. Be careful!

-Geoff

So is there any way to fix that and not get that problem? Is it really dangerous?Thank you

[JSH]

You need to read and understand the codes it's throwing, so have your dealer read them, or buy HP Tuners or