Car Pulses during accel and cruising?

[Max777]

Yeah, so here I am yet AGAIN.

I have figured out EVERYTHING except fo this stupid problem on my car.

When I drive on the highway, i get this constant thub thub thub thub type of sound... however, it seems to be constant, and even happens at a simmilar rate when I'm accelerating from a stop as well, cruising at 3000 rpm in 4th, etc...

So far I've done this:

AFM
TPS
Driveshaft
New rear tires

That got rid of everything but this problem. It's not significant enough to where I cant drive the car, but it is annoying as all hell. I've tried to diagnose it to no avail... help please.:o11:

[vex]

Have you figured out if it's speed related or engine rpm related? That will go a long way to helping diagnose the issue.

[Max777]

Well, when I accelerate, the "pulsation" goes like this:

instead of the engine revving like "vrrrrrrrrrrroooooooooooooooom"

it goes "vrooorooorooorooorooorooovoooooooovooooooovoooooom"

Almost like it's rpm dependent, yet gets more "infrequent" as the revs increase?

And then I get this on the highway: "vroooom vroooom vvroooom vrooooom"

[Rotary#10]

maybe you could record on video with a friend to show us whats happening.

[TitaniumTT]

ECU and timing map
What are L readings while it's happening
how old are the plugs and wires and what are you using for ignition

[MazdaMike]

Did you properly adjust the TPS..you know jumping the initial set coupler and blah blah blah. Are you 100% sure you have no vacuum leaks? They can seal and open in relation to engine temperature. I would check between the extension manifold and the LIM...its common that people remove the upper intake assembly from there and its possible that constant improper removal process has warped the manifold or made the gasket fail.

[junito1]

My car seems to accelerate in a pulsing manner also. A common driver would not be able to pick up on it. I think the OP made it sound a little too exaggerated.
I feel mine under light throttle/load acceleration. Anything near 0 vacuum is not noticeable.


I suspect one of my injectors being leaky or maybe the fact that there is 6psi diff in compression ratio between f/r rotors.?

MAybe the fact that i have full s4 TII efi running a s5 block. (heard spark plug holes area bit diff from s4/s5blocks)

MAybe its normal for a rotary?

[Max777]

Plugs JUST got changed, plug wires all show simmilar resistance. They were around 5K ohms and 8k ohms last time I checked. I set the coupler, adjusted the TPS to 1K ohm at idle, and set the idle to as close to 750 as I could.

I checked the timing, and it's dead even on the leading side, but the trailing side #1 plug shows the timing a little off when it's hooked up.