87 3800 to 4000 rpm hesitation
 

Hi, I've been fighting this hesitation I've checked and replaced grounds even did the ground part of the big 3 upgrade which made it hesitation worse if you can believe it kinda lost on this and thinking about maybe just swapping over to a carb setup

Have you gotten your injectors serviced?

I cleaned them when I rebuilt it and had it all tore down I'll try to get it in the shop and pull em out and check em out I cleaned them myself just like I would with any other injector they seemed to cycle and not stick or anything

Get the auxiliary ports working. They are probably seized.

I had/have this issue. I've addressed grounds and still no success. I got my car way when I bought it so I started to look over the whole thing and found that they had installed high impedance injectors on my secondaries. I got some low impedance injectors from a friend to replace them and they were also "cleaned" with spray methods. It fixed my problem for a short while then quickly came back and got worse!! I sent the injectors to get ultrasonic cleaned and boy did that make a difference! Its virtually gone once the car warms up. I believe the only reason why it's not 100% gone could be that I didnt clean out the primaries, just secondaries. So I think when the secondary injector cycle kicks in, theres a very slight hesitation where the primaries arent as clean as the secondaries now. I'll be taking those out to clean them and I should be 100%.

You could try changing the fuel filter if you haven't yet. I know it sounds simple, but lack of flow could cause you to lean out when the secondaries kick in. But like they said above, good things to check would be the injector part numbers to verify impedance, clean injectors, inspect the connectors, and it looks like you took care of the grounds already.

As stated, if the grounds are clean and tight, replace the fuel filter, and have your injectors cleaned professionally. They will flow test each injector to ensure that each one is spraying properly. If anything, its peace of mind knowing you can rule it out. This will give you the opportunity to inspect the connectors for the fuel injectors and ensure the wiring has no breaks in teh shielding or wiring and that the pins are clean and tight.

Ensure you do not have any vacuum leaks. Inspect the spark plugs and replace them if they are worn. Do the same with the wires. Have you checked the coils per the FSM? Coils do not usually fail, but its good to rule them out. It also wouldn't hurt to perform a proper fuel pressure test to ensure the proper amount of fuel is being delivered through the rev range.

This may sound stupid but if you have the high tension leads mixed up it will mimmic the dreaded 3800rpm hesitation. I'll admit that this happened to me one time where I put leading on trailing and vice-versa and I was hesitating hard when the secondaries kicked in. I know it's a long shot but you never know.

there is also a sock on the pump in the tank, i dont know what it could look like by now but might be worth an inspection

Wish mine was turbo so the fix would have been this easy haha.

If you do take your injectors to get professionally ultrasonic cleaned, try to do all 4 at once. I did just my secondaries because I thought that was the issue but I now need to go back and send the primaries to get cleaned. I have kind of a reverse effect now where 3800 rpm sends it into VTEC mode. It goes from accelerating normally to what feels like boost (I have an NA). I believe this is because the secondaries are basically brand spanking new and the primaries are probably pretty clogged.