Hey guys I have a 94 3vze pickup, it has around 230k miles on it and it previously had a problem with misfiring/jerking whiledriving and kind of having little tiny misfires/stumbles at idle every few seconds not really a big noticeable thing but it definetly wasn't a perfect idle.. I then replaced cap, rotor, ignitor, coil, and then finally spark plugs and the plugs fixed the issue! For a few days the idle was perfectly smooth and flawless but then it went back to normal again but still drove fine and didn't misfire one bit. 3 or 4 months have gone by and I can tell it's slowly beginning to not run as smooth. When warm and at idle it kinda surges a little and when just cruising at a constant speed it sometimes won't go real smooth it jerks like it wants to either get on the gas or let off... it is very frustrating and I'm almost positive it's the plugs again. I put the cheaper ngk plugs in last time from autozone that they told me were the plugs to use. I'm not sure if I should just get the iridium ones or what but I'm just an amateur 17 year old mechanic that has a part time job lol don't have loads of money just want it to run smooth again. Truck has no cat and a flowmaster cat back exhaust and also a cold air intake not sure if I can make it run more lean? Any help is much appreciated

 

Also forgot to mention truck runs better on higher octane fuel also

 

Check your 02 Sensor. Most 3.0 running rich issues seem to relate to the 02.

Have you checked your AFM or TPS?

 

I have not checked any of those, how would I go about doing so? I'm pretty sure the afm is fine but I can still check

 

Found a small hole in one of the plug wires and replaced the wires and the plugs with the non copper plugs(recommended by dealer) seems to be a little bit smoother but on colder mornings I will start the truck and it will barely idle like about to die for a few seconds and then rev up to warm up rpm, not sure what the deal is but also when it's cold it does as I said previously how it's like it's not running on all cylinders starting from a stop it's the worst. You get on the gas and kinda revs up like normal but it just doesn't go anywhere and then after a little bit it's like the other cylinders kick in and it goes... Also at idle it has slight surging. Really any help is useful!! Thanks

 

Kind of in a bind here, truck quickly went down hill a few days ago, it would barely get me to school and back. It would just completely want to bog down and die everytime you wanted to accelerate so I broke down and got a new tps. It definetly got better to where I can drive it but is still having the same issue. We put a diagnostic scanner on it and nothing really looked out of the ordinary. Really needing some help here on what to look into next

 

1. Short in Wiring Harness also checks for bad grounds.
2. Bad Coolant temperature sensor and / or connector.
3. Fuel pressure regulator.
4. Check Ignition wires for short.
5. Spark plugs wires.
6. Adjust air flow meter.
7. Check ignition timing.

 

1. Throttle Position Sensor / 2. Fuel Pressure Regulator / 3. Mass Air Flow Sensor
Can replace (1. 2.) Clean or replace 3. fairly easy. Shop around online. Best advice I ever got was to go stock with the spark plugs. Don't F'k around thinking these "upgrades" will do much for you. First, understand the Japanese method . . . these trucks are Spec'd to function the way THEY intended them too. Slight changes, even the so called "Cold Air Intake" will force your ECU to try and "translate" new dynamics to a basic engine. Keep it simple. This isn't a Ford! I have a 93 3vze with 350,000 and have gone thru all ˟˟˟˟˟ you are experiencing. Start basic . . . work your way up.

 

Check your 02 Sensor. Most 3.0 running rich issues seem to relate to the 02.