looking for a little help with my 1993 Bravada. it recently developed a miss fire at low RPM. if I am going about 25-30 it misses, at idle and hard acceleration it is fine.
fuel mileage has not changed, exhaust does not smell like gas, fuel pressure is good, all spark plug wires are tight and I do not have any codes.
I am thinking the distributor has quit on me and was looking for some other general troubleshooting help.

thanks for any help!

 

try the cap/rotor first. For some reason these things like eating dizzy caps.

 

Chris015,

thanks for the reply. I will check it out tonight.

 

First thing before tearing it apart. In the dark start it up and look at each wire while its skipping and look for arcing/sparks. Could have a bad wire also

 

If you have a scanner that has a live data view you could check the signal from the throttle position sensor. They can wear out and cause part-throttle problems.

 

no, I do not have an OBD 1 scanner. I was using the blink code method for the service engine light. 1 long blink and 2 short blinks is all I get.
drove it home for lunch and it was missing horribly, drove it back to work and all of a sudden it was running like a champ again.

 

checked the distributor and looked good. disconnected the sensor in the air intake just before the throttle body and it ran better, miss didn't go away, but it ran smoother between 25-30 under light to moderate acceleration. checked the throttle position sensor and it was dirty, really dirty. cleaned it up and it ran worse.
I am not putting any more time into it at this point as I am putting it up for sale in the next few days.

thanks for all the help!

 

Ok, so I couldn't let it go. I popped the hood again tonight and I checked the distributor again and cleaned it up a little.
Started it up and it still ran rough, sounded like it was out of time. Loosened the distributor collar and adjusted by ear at idle and got it running smoothly. Road tested and it still would miss under light acceleration from 0-20 mph.
Unplugged the MAT/IAT sensor in the air intake tube and road tested again, this time with much better results!
Take off and acceleration are better than ever.

 

bump.
well it's back and worse than ever, not sure what the heck is going on since this thing isn't producing any codes.
replaced intake hose that holds the IAT, new temp sensor, new knock sensor pig tail, new fuel filter, cap, rotor, wires and plugs.
compression test, again, yielded same results as before. tested coil and fuel pressure and all good. at idle it's fine, trying to accelerate from a standing stop is almost impossible unless I mat the gas pedal. hard acceleration is fine, problem comes and goes too which makes it more frustrating.
any ideas?

 

Have you removed and cleaned the EGR valve and got the new felpro gasket for it with the screen?