I did a search and there seemed to have many different solutions to the same problem.

First off, I posted in the transmission & drivetrain forum first because I thought it might be a drivetrain issue. That description is here:

https://honda-tech.com/forums/transmission-drivetrain-127/another-shuddering-acceleration-thread-2583491/

As far as the motor is concerned, it is the mild LS/Vtec with:

p30 pistons, stock rods resized with ARP rod bolts
b16 head, blox B cams, S2 springs and cam gears
AEBS IM and PP TB
Hondata s100 p28
Walbro 255
NGK V-power BKR7E Plugs
Auto Zone el-cheapo plug wires (ashamed to admit, but possibly relevant)

NO CEL

I used to have the Hondata IM gasket, but I kept having problems with it leaking coolant so I recently swapped it out for a stock paper gasket and replaced all the coolant. I have heard maybe issues with an air bubble in the coolant messing with the IACV?

What is happening the shudder/hesitation on acceleration from idle-ish to 3000 RPM and then it kinda isn't noticeable. Also something when I do rev it out and to a hard shift into the next gear it bogs under WOT and then comes back.

Does this when either hot or cold. Doesn't matter.

Throttle position makes no difference other than more or less load on motor.

I pulled the plugs and they are a healthy bronze color. I have yet to do a compression test, but I will tomorrow. I just hate taking off the crappy plug wires because it feels like they don't go back on tight. I will be replacing these ASAP with probably some NGKs or suggestions?

There is also a slight tic in the valvetrain. I will check the valve clearances. When I had my tune done, I installed my cams/valvetrain the previous night and did not have the proper tools to to an adjustment so when I drove to the tuner the next day he had to do a lukewarm valve adjustment.

Thanks in advance, and please let me know if you need any more information.

 

Hmm..

I would do a compression test just to be sure. Then change out the spark plug wires for some NGK plug wires. Also maybe put a new distributor cap and rotor and fuel filter. Has the distributor timing been set correctly to 16 degree?

Let the engine cool and then do a proper valve adjustable.

Also, were the cams timed correctly?

This is start.

 

Did a compression test today:

210-210-210-200

That at least seems pretty healthy w/o doing a leakdown test.

My NGK plug wires will be in tomorrow morning as well as new plugs just in case.

I will get a new cap and rotor too from the dealership unless there are other recommendations. I try to stay OEM as much as possible.

I did have to add coolant today when I checked. I would say probably like 20-30 oz. I will keep an eye on it to see if it goes down again.

My dizzy is pegged advance. I remember when I tried to set my timing when I had my first Phearable chipped ECU, I could not get timing past 14 degrees advance. My tuner didn't move the dizzy, but I informed him of the issue I was having with the Phearable chip. Funny when I had the stock OBD2 p75 ECU plugged in, I could get 16 degrees of advance pretty much right in the middle of the dizzy adjustment. It will probably be different now with a different tune.

I will check the valvetrain adjustment on my next day off which is Sunday, unless the wife lets me take the MDX to work sooner than that.

The cams were tuned as well. +2 and -2.

Also, does anybody know if there is any allowable play between the IM shaft and the Driver side axle? I couldn't get any answers in my thread in the drivetrain forum.

Thanks again.

 

Swapped the plugs and plug wires. No change...

 

Have you considered your Distributor might have seen it's fair share of days? The first thing that came to my mind when i read your post was timing, the second was a PCV/Vacuum leak or even your EGR valve(but that throws a code 90% of the time), but not plugs and wires....not if it bogs down, then picks right back up. how is your exhaust system looking? my buddy had a similar problem, which turned out to be a clogged cat.

 

decent mod list, but no upgraded injectors?

 

Well, first off to answer the questions:

There is no EGR valve.

Exhaust is a JG Edelbrock ProFlo header w/ 2.5" collector mod, 2.5" to 3" test pipe, and a full KTeller 3" mandrel bent exhaust. (I will be built K some day)

I still have the stock injectors, FPR and Fuel Rail. My tuner (10secivic) was able to achieve optimal AFR without going bigger. He said that the fuel system is maxed out and any other mods would require more fuel, but it did put down 180whp on his Mustang Dyno. That was also before I added the Walbro 255 (because I plan to go nitrous.)

Still haven't checked the timing...


However,

I swapped out the drivers side DSS axle for a fresh OEM Reman axle and the shuddering went away!!! I sure hope those guys customer service is far better than their products. I have had nothing but problems with BOTH axles. The passenger side axle refuses to seal into the transmission causing the $8 per quart MTF to **** all over the place. So right now I am running on 2 OEM reman axles. They hold up fine as long as I am not running my slicks. I am gonna call up DSS tomorrow and see what they will do for me. I just bought the axles (2.9s) back in January and they have less than 1000 miles and 50 drag launches on them. Plus this time the drivers side axle went out during a spirited drive in the country doing a hard upshift on heat cycled RA-1s.

Also it doesn't bog anymore on hard upshifts. This is probably from swapping the plugs and wires. I didn't replace anything else. I am sure it won't hurt to replace the cap/rotor and the fuel filter. I have no idea how many miles the B16 head/distributor had on it when I got it and the chassis has 177k on it, so who knows when the fuel filter was changed last.

Well it looks like no more drag racing for me, only circuit track days.

 

you might want to pick up new shaft seals if it's leaking between the axle and transmission. it's that (usually red) colored gasket/seal right inside the transmission that prevents fluid from flowing out.

 

Already did...