89 Problem

Hello all,
I am in need of some help on this one!
I have an 89 nissan pick up 4wd 4cyl.
Here is the problem:
When it is neutral it has a miss & doesn't want to idle
but if you give it gas it doesn't idle to bad but you can hear it miss
But when you try to drive it, it's a whole different story.
It bucks and jerks like it either has water in the fuel or its running
out of fuel. But them once you get going up into the rpms its not
as bad. But if you use more than half throttle it bogs .
Then after you drive it for awhile and stop, it will idle at (where I have
the idle set at ) for about a half second then it idles down and stays there
for maybe a minute and then the idle will go back up to where it is
set for about a half of second and then back down.
This is what I have done so far:
new cap & rotor
new plugs
pumped the fuel tank added new gas
new fuel filter
checked for vacuum leaks
With no avail!
If anyone has any suggestions what this might be it would
be much appreciated.

Thanks in advance

check the codes.

Any other suggestions this thing is driving me crazy

did u check the codes?

if u did then post the numbers..

Did you change the filter before or after the fuel tank drain?

did you check your injectors? i have seen them go bad. If they are dumping to much fuel or not enough .. you want to check the spray pattern and check you Resistances with them, i would check that:smokin:

Hey all

Ok I had the codes checked at 2 different shops
and both said it did not show any errors
So ?????

Would a bad O2 sensors cause this ?

try looking at the timing chain and tensioner for wear....

have your injectors checked while your at it, some places do it for low price with cleaning while it's out. o2 sensor will only adjust/compensate for what is already throwing air/fuel mixture off up to a certain point then it reaches max limits and you'll have to find out what is causing it. idle air may need cleaning, usually affects idle. egr off idle, maybe need to clean passages. I don't owna nissan so just guessing.