Poor Acceleration

[robertr1229]

Hello All,

Long time lurker first post, I have a 90 NA That is Accelerating poorly. I have done many searches on multiple forums and looked into hesitation issues. I have the Datascan software and adapter. Here is what I have looked at and done so far:

1. Replace Fuel Filter
2. Check Air Filter and Sensor
3. Checked Timing (With Light and Datascan)
4. Checked TPS
5. Checked IACV
6. Replaced Plugs
7. Checked Cylinders by removing coil pack connectors
8. Checked For Vacuum Leaks

I am literally a a loss here and wanted to see if anyone had any ideas?

[nissanfreak12]

How are your O2 sensors, the will easily cause hesitation. I know the O2 heater on mine is either out or going out so I have horrible hesitation until I at least get up to a quarter in temp.

Coolant temp sensor is another one to look at, sometimes it doesn't read on the ECU, but if its not reading right it will also cause hesitation due to under or over fueling.

I know you have checked TPS, is it set correctly?

How is your fuel pressure? Pressure regulator?

These are some things that come at the top of my head, I know there are more, but its a start.

[Ziggy1621]

Welcome to Nico! Ill second the fuel pressure. If it idles fine, but hesitates when under load, most of the time you can figure it out with the air/fuel ratio

[t.mcginley.jr]

Also, when you said you checked the air sensor (MAF) did you just look at it or did you clean it? if not, cleaning it with MAF cleaner isn't a bad idea.

[Ziggy1621]

Another good option is to have a USB to ODB tool. Then you can download a free program like ECUTalk and plug it up. It is a good thing to have if you plan on owning this car for any amount of time