Hey guys, I've got '91 dlx pickup with 184,000 miles on it and I've been experiencing some strange problems. Every once in a while I will be driving down the road, and I feel this crazy jult happen out of no where. It always happens during acceleration, and has happened in most gears I believe. I notice it happening while in 2nd and 4th mostly. It jults once, and resumes accelerating normally. It is a slowing jult. this used to happen three times a month, but now its at least twice daily.

I've been looking through forums and my manual and from that I've read, I believe it's some sort of intermittent misfire. Can that happen without getting a trouble code of some sort?
So far I have checked my compression and tested the ignition system resistance. Everything is normal there, getting an average of 130 psi in all cylinders. I did notice that the plugs from cylinder #1 and #5 had pretty major carbon buildups and partial decay, and all of the plugs are only 10k miles old. I plan on checking my fuel injectors tomorrow, but if it is an intermittent misfire would you even be able to tell that an injector is bad by listening? or would it just sometimes not work?

Thanks for reading, can't wait to hear what you guys have to say!

 

Are you running an automatic or manual?

 

I have a manual tranny!

 

Wow, I have a similar problem: 1994 T100, 4x4, AT - 3VZE Once in a while, the truck just "hiccups". I thought I fixed it by putting a new grounding bolt for the ECU, but it is still happening. It can happen anytime, not just acceleration but straight driving or even in lower RPMs. Like you, no codes. It almost seems that the whole electrical system dies for just a scant, less than a second, moment.

The only thing that I have noticed is that my air bag light comes on for a brief nano-second after / during what you described as a "jolt". Which is weird, since that air bag system and main ECU are really separate computers. Sorry I can't help you at this point in time, but I do feel your concern. I just don't want to be sitting on the side of the road when I know there is a problem, but I have no idea what it is. My suspicions are a bad ground somewhere but my assumptions can be far off. If I find out what the issue is, I'll post it ASAP.