Hello I have been reading this and other forums looking to solve this problem that has me pulling out my hair.

My 95 Chevy will misfire/jerk when it’s warmed up and accelerating. It is throwing no codes.

I have already done the following,
new spark plugs, wires, distributor, coil pack.
new fuel pump, fuel filter, and checked the fuel pressure (it’s fine).

no smoke from exhaust. Doesn’t miss fire while warm and idling or reving in park.

what has me in a loop is no CEL or codes to check.
my next “try” is going to be new throttle position sensor and coolant temp sensor.

is there anything else I should be checking for? This is a family truck that’s been with us since it was bought new by my grandpa in 95. Regular maintenance done and the such. He passed 2 years ago and was my go to for any problems like this.

thank you for any input

 

Welcome - arer you seeing a change on the tach when this happens? Wondering if it's transmission and not motor??

 

Yes actually, when it happens the RPMs will drop down for a split second then return to normal.

 

also, it does seem to happen more when in Overdrive.

 

Try driving in "D" to lock out overdrive and see if it keeps happening

 

I have overdrive then, 3, 2, 1

I have been driving in 3 for a few days to test just that. It still happens once the truck warms up. And with the weather warming up here, it is happening quicker and more frequently.

 

Another note, when the truck is cold I can get going through all gears smoothly and accelerate fine.

 

The issue you’re describing is indicative of the fuel supply leaning out on acceleration. Pressure may have been OK but the volume of fuel being delivered is also important.

Remove the fuel line at the throttle body and use a length of hose to direct it into a container. Jumper the fuel pump relay for 5-10 seconds and measure the amount of fuel collected.

The general specification is 1 pint in 30 seconds, so do the math on what’s collected to determine if it’s supplying adequate volume.

If it’s got good volume, can you set up to monitor pressure while you’re driving?

I’m also curious if the fuel in the tank is old or possibly the wrong mix (too heavy of an ethanol mix). Any idea what the fuel quality is?

 

Update : replaced fuel pump, drove about 15 miles. Once warmed it started missing again, on the highway. Eventually to die when I pulled into the drive way. Would not restart until engine was cool

 

Check the connections at the injectors and see if there’s any fuel seeping out of the injector body when it’s warm.

Post pics if you’re not sure.