Hi all,

I searched through the forums and couldn't find anything related to this issue. I recently purchased a 1992 Pickup 4x4 DLX manual transmission with the 22-re engine and about 118k miles on it. It's completely stock and overall runs great with no issues. After driving around for about an hour I got a litany of codes that ended up being fixed by cleaning the mass airflow sensor. No codes since then, until I installed a new air filter. I installed a K&N 33-2050-1 High Performance Air Filter. After about 25 minutes of driving after install, the check engine light came on with no notable issues associated with it (that I could tell).

I checked the error codes and got Code 25, lean mixture. I'm assuming this is because of the higher flow air filter. I would prefer not to go back to stock filters and was wondering if this is a known thing- the ECU/injectors can't push enough fuel to keep up with the new air filter? I didn't think it was going to be a hugely significant change when I switched. All thoughts are welcome

 

Your truck does not have a mass airflow sensor. it has a mechanical VAFM

Generally, engines that use vane air flow meters do not do well with oiled type air cleaners.

Sooner, or later, the VAFM will be fouled and ruined by even the slightest oil introduced into the intake stream from a K&N type filter.

 

Oh wow, I had no idea! Thank you @millball for educating me on this. I will go back to the stock filter and comb the forum to see if there are any recommended filters