I've had my 94 Jimmy for a while, chased down many issues since I bought it. Everything is working good. 18 mpg average. Good acceleration. But It has a skip that sounds like a puff of air from the tailpipe every 5-10 sec ONLY AFTER it warms up. Its done this since i've changed the dist, spider inj, egr clean and screen, even a new coil and plugs... Do they all just have this mild skip, it's really not noticeable. Most passengers never notice until I tell them to listen for it. The engine doesnt even visibly shake. So, does every 4.3 cpi engine have this little skip?

 

Yup pretty much. I think it may have something to do with the batch fire injection cause the MPFI engines don't seem to do this.

 

My CPI does this as well. same with my 94 when I had it.

 

Uyp , throttle body! This is the one benefit of a throttle spacer. When I put a little higher speed stall converter the slight skip got worse. When I put the spacer under the throttle it got half way better. You might bump your throttle stop a LITTLE (use a dvm i forgot the voltage) and make sure your egr isnt leaking.

 

what's a CPI folks? and how does when check to see if an egr is leaking?
18mpg is the best i've seen posted. i'm curious what mine will do here. any opinions on a k and n air filter?

 

CPI= Central Port Injection.
MPFI= Multi Port Fuel Injection.

CPI has one injector that feeds the entire motor.
MPFI has an injector for every cylinder.

Someone please correct me if I am wrong.

i dont know about the EGR though. and last weekend i averaged right around 20mpg in mine. but that was mostly highway. i averaged 18 before that when i drove to about 150 on the highway, up and over the Grapevine (one of the big hills in southern cali), to Bakersfield. Launched a boat all weekend for the boat races and did a little bit of 4 wheeling.
K and N filter IMO isnt worth the money.

 

wicked. thanks!
so is the spider injector a multi-port? or is it a single center injector with 6 legs coming off of it for each cylinder?

k and n not worth it due to it not offering more air flow? or no more power than a generic filter? i'm curious simply for the mileage.

thanks again.

 

its a single injector with 6 legs, hence the "spider"
and no matter what you do, it will still have that "skip" I have a k&n filter and it does the same thing. I kinda like it LOL

 

i would say both. i had a 95 that had over 315,xxx on it and it got the same gas mileage its whole life. had several different brands of air filters. same performance with all of them as far as i could tell.