My 1989 Ramcharger started having a dead spot upon acceleration recently. In park or neutral it revs up just fine with no hesitation. When in drive, there is a dead spot and then it catches and accelerates normally. When I punch it to the floor it kicks down with no dead spot at all. I have replaced the TPS and MAP sensors. There was a 15 code indicating no signal from the speed sensor. Replaced it and no change. There was also a 21 code concerning the 02S sensor. The PCM has been replaced last year also. I am running out of things to replace. Even replaced throttle body injectors last year. Any help would be appreciated.

 

21 Oxygen sensor signal doesn't change

Have you checked fuel pressure? Replaced the fuel filter? See if you can get a scanner or app for your phone to read live data. That will show you if there is a problem with one of the sensors.

 

I put a new fuel filter on several years ago when I bought the Ramcharger. I'll replace it again and also check the fuel pressure. Thanks for your response.

 

I replaced the fuel filter but no change. However, my Ramcharger has 93k miles on it so we hooked up a vacuum gauge and set it to highest vacuum then backed off one atmosphere. That fixed the issue but now it stalls sometimes when coming to a stop sometimes. I plow with my Ramcharger and when changing from directions back and forth it sometimes stalls. Starts right up and actually starts much faster than before. Adjustment for curb idle on my 89 Ramcharger throttle body?

 

 

Thanks!