Nissan Repair: 89 HB wont rev past 3k rpm, mass airflow sensor, air flow meter

Question
QUESTION: I have a 1989 Nissan HB truck with the V6 (auto), and I'm having some trouble.

It idles a little rough until it fully warms ups (down around 500 rpm), but once it is warm it idles fine like normal around 900 rpm and I can rev it smoothly up to 3000 rpm. The problem is, it won't rev past that, it doesn't seem like it wants to die but just won't rev past 3000 rpm.

Is there a sensor that controls higher rpm?

I haven't started the truck in about in 3-4 weeks, but the last time it ran fine with no problems, but now today that I started it, this problem showed up.

Any ideas/suggestions of what to look at?

Thanks

ANSWER: Glen,

Check for a blocked converter on the exhaust.  The last one that I worked on that would not rev past 3000 was a melted converter.  Email me back with what you find.

---------- FOLLOW-UP ----------

QUESTION: I pulled the code through the ECU and it shows a Air Flow Meter error. could this possibly be the problem that is keeping it from revving past 3k rpm? I haven't had a chance to pull the converter off to see if that corrects the problem.

Thanks,
Glen

Answer
Glen,

Yes it would and you found the problem.  Be sure to disconnect the battery before you change the mass airflow sensor and do not hook the battery back up until you have the new one installed and plugged in.  Be sure you ground yourself to the vehicle by touching it with your hand before you install the new mass airflow sensor as a static charge can kill the new one.  Make sure you do not touch the inside of the mass airflow sensor when you install it.  Then reconnect the battery and you should be good to go.