I've been trying to diagnose a bogging problem on my OBD I 94 Ram.

After the engine has been thoroughly warmed up, if I punch it from a stop it revs fine to about 1200 rpm, then boggs, the rpms drop slightly and I have to let off the gas to continue to accelerate. It runs great above 2000 rpm and accelerates fine under less aggressive throttle. It does not have this acceleration problem before it's been warmed up.

I checked what sensors were easy enough to get at and found most of them to have questionable readings so I replaced the IAC, TPS, O2 sensor, and MAP. The ignition coil reads 0.9 ohm and 14.8k ohm. The 14.8 is at the upper end of the Diamond brand specs, and is out of the Toyodenso specs (I don't know which it is). I have no Cat at the moment, but just had one on and my exhaust tested very low hydrocarbons and CO but barely passable nitogen. I'm getting 14.8 mpg.

Any ideas?

 

For the price of a new coil, I'd go ahead and replace it since the readings are questionable anyway. If that doesn't do it, I'd take a hard look at the crank sensor. I just learned the hard way that it can cause misfiring/weak, intermittent spark without being completely bad. (Same exact year and engine as yours).

And I hope you reconsider your decision to run without a cat. (Yes, I'm one of those).

 

I don't suppose there's an easy way to get at or test the crankshaft position sensor, camshaft position sensor, and coolant temperature sensor? Is there a scan tool that can do more than just grab codes for OBD I?

I just had my catalytic converter on for an emissions test, and the whole thing (factory original 2in 1out pipe system) was riddled with leaks. After spending hours trying to fix the original welds and connections, I still had an exhaust leak and gave up on it. The hydrocarbons and CO were extremely low, but the nitrogen barely passed.

 

https://dodgeforum.com/forum/2nd-gen...um-thread.html

 

I did the vacuum test with two different gauges. One gave me no reading, the other read a slight pressure increase. The plenum gasket was resealed by a shop at the tune of $520 by the previous owner a couple years ago. I don't get any pinging or oil consumption, so I'm hoping that's not it. It seems like a distinct possibility though.

 

The higher nitrogen makes me think that it is running lean.

 

Anybody?

 

Have a look at fuel pressure while you are accelerating. A gauge with nice long hose will be in order.... so you can see it while driving.