Ford Repair: Engine Knocking, oil pressure gauge, mechanical oil pressure gauge

Question
I have a 1988 F150, standard transmission, 4.9 Liter 300ci. and just started to notice a knocking noise coming from what seems to be the bottom of the motor during take off from a stopped position or while going in reverse, and  at low RPMs'?? Also at start up after it sits for a few hours but the noise seems to stop while driving it at normal speeds and on the highway. I was told that it was probably a Rod tapping??Any information at this point would be helpful.

Answer
Hello and thanks for the question...I'll try to help.
With out hearing the noise....I couldn't say. What I would suggest is that you put a mechanical oil pressure gauge on it and see what your oil pressure is. Also, change the oil and filter...... use a summer grade oil....... 10w40.
Hope this helps,
Erik