A while back my jeep started missing kinda bad. When i go to start it, it cranks a lil then starts. And at idle, it misses bad and puts almost. Then once i get going, if i go from high to low rpm's, it lunges really bad and has almost 0 power. We've replaced a bunch of sensors and all the spark plug wires and dist. cap. What could this be?

 

TTT

 

Have you checked the fuel pressure? Any CELs?

 

Ya i had it tested, and we checked the engine for any codes, and nothing.

 

Crankshaft Position Sensor could be bad. I don't think they throw a CEL for that either.

 

You did check/gap the plugs.

 

Yep, checked the plugs and firing order. Non of them are fouled.
It's gettin worse though

 

You did check the gap? Even new ones should be checked. They are way to important to shine that simple task. The gap grows a little every day, then idle will get bad and it will start to stumble and miss.
I mean I guess you DID, I just don't see "checked the gap.......Do you know if it's time for a fuel filter?

 

Now i feel dumb here, but what do ya mean by the gap?
And i'm gonna change the oil, and oil filter this weekend, along with fuel filter.

 

He means spark plug gap.......mine is .035 in

cpnwrench

 

oh yeah........this REALLY may sound dumb.......but I am gonna say it anyway......

new wires and cap etc. right?

are you 100% sure that EACH wire connector had an AUDIBLE and a TACTILE feel of a "click" when you attached them to the plugs

( I have a hellava time with these when I have changed the wires)

are you 100% sure EACH spark plug is snugged into its hole tightly? (not gorrila tight, but tight).

an last but not least, you got a new rotor with cap right?

cheers!

cpnwrench

 

has the distributor been pulled and reinstalled? maybe off a tooth? is the timing chain stretched? if neither of these and you know the plugs, wires, cap, rotor, firing order are all good, check your coil, your crankshaft position sensor, and your camshaft position sensor. isn't much more to it.

 

Hey...this is what this forum is for! When you have the plug out, it's the space between the little tip there in the center and the "J" shaped thing. (those are the electrodes". I like the plug gapper that is like a 1/2 dollar with different widths around the edge. There's also wire types that may be more accurate. Also I have a deal like pliers with a wheel you turn to select different gaps. Then, after a few 100 you can almost do it by eye.

 

Found the solution, i had a broken solenoid on one of my spark plugs, and a bad gap. But now the ol jeep has a real fine vibration, AND has low pressure to the 1 and 5 cylinders.

 

Huh? Low compression? Spark plug solenoids?