Still having probs, need help bad

[rockinthefans]

I have a 92 hatch with a fresh kade. It has a bad hesitation pretty much all through the rpm range when under a heavy load. If its only at light throttle its not nearly as noticable. It does it no matter if its hot or cold. Idle is perfect, constantly 700 rpms. It just feels like when I have under heavy acceleration that im actually slowing down, like Im letting off the gas when Im really on it. Weird. Before people start screaming seafoam, this has been going on for a while now and I've replaced tons of stuff. The motor only has 1500 miles on it since its rebuild. So to help out here's a list of stuff that I've done/replaced:

Z32 ffngk plugscomplete emission delete. only vacuum source left is to fpr.fuel pressure is 36 psi at idlenew tps installedcleaned mafreplaced knock sensor and replaced wiring to ks

I just ordered an oem o2 sensor for it and I'm gonna put it on tomorrow. The other thing is that I get exhasut backfire when Im driving and I let off the gas but its mostly at lower rpms which would lead me to believe it would be a vacuum leak but with my idle be very consistant it doesn't make much sense. i know it runs very lean because my plugs are pretty much white oh and that fact that my narrow band a/f gauge says so lol. it dances back and forth for a while but after about 10 or 15 minutes on the highway it stops and stays steady at stoich for a minutes then fades to lean. Im stumped as hell and dont know where to go next. I really need to get this fixed. I got 4 grand in this motor and cant even enjoy it. Any ideas?

[onosqv]

have you done the simple things, such as check your base mechanical timing?

since you did an emission delete, have you checked for vacuum leaks in areas you have plugged up?

checked the fuel injectors to make sure they are working correctly?

check compression to make sure the rebuild was good?

check the coolant & oil to make sure there are no weird mixes?

if you don't know how to do these steps, you can search for the factory service manual & download it here.

[Hijacker]

The rings may have not seated in yet. Depending on the manufacturer of your pistons and rings, the break in process can take longer or shorter.

I'm assuming you replaced all the sensors (primarily coolant is what I'm wondering about) when you put this motor together. A faulty water temp sensor can cause horrible things with your A/F ratio.

Also, make sure your TPS is set properly. Some people tend to remove the TPS when they clean up the throttle body and it gets reinstalled set incorrectly.

Make sure your ignition timing is set properly. KAs should be 20 BTDC (stock setting, you might have it advanced a little)

Double check that the MAF plug is seated properly and you have no leaks in your intake pipes.

[rogoman]

How about something simple as replacing the fuel filter.

[sittinsideways76]

Im having pretty much the same problem. when I hit a bump on the road the rpm willl go crazy and the car will hesitate, the car usually runs fine when its cold but not all the time. Ive changed MAFS and Distributors and motors mounts. the new dizzy and mounts helped at first I thought it solved the problem but then it started happening again. I feel overwhelmed trying to find out the problem as it can be so many different things. Someone also told me it can be the Crank sensor

[rogoman]

Im having pretty much the same problem. when I hit a bump on the road the rpm willl go crazy and the car will hesitate, the car usually runs fine when its cold but not all the time. Ive changed MAFS and Distributors and motors mounts. the new dizzy and mounts helped at first I thought it solved the problem but then it started happening again. I feel overwhelmed trying to find out the problem as it can be so many different things. Someone also told me it can be the Crank sensor

Check the electrical ground connections.