Konarider321

My 90 5.0 lx is giving me trouble and I could use some advice. It runs fine when its cold with no problems for about 6-10 min then sputters/misses a little, once every minute of so for a few miles than gets more frequent. It's gets so bad it barely runs and has stalled a few times, but it's always started back up and continues to run like crap. It has stalled a few times at idle and once while driving. It's worse under load but sputters at idle when it's really bad. I replaced the cap,rotor,wires and plugs and it runs the same (the cap was hammered). I put my hand on the fuel rail and line after limping home one time and the line was warm but not hot. My guess is something's getting hot but what? I did a visual on the MAF sensor and it looked fine, no crud. It's has a full offroad exhaust and an aftermarket radiator nothing else

dawson1112

Could be the TFI module on the distributor is going bad. Pretty common when they get hot to start missing and bucking , even stalling and have to wait a few minutes for it to cool down before it will start again.

Could be the coil is breaking up once it gets hot, heat causes ohms in resistance to rise, making it difficult for the coil to do its job.

Faulty ignition componants tend to show them selves first when they get hot, eventual failure is immanent

88 orangepeel notch

+1 ^^^

If those check out, then check fuel filter. I had a F150 with those exact problems, the fuel filter was plugged tight.

camaroeater

Even though the rotor is new, check the tension spring on it to makes it has proper tension.
I once had a defective rotor with the same symptoms you explained. May not be your problem, but it takes only a minute to check.

Konarider321

Swapped the tfi module out of my dads 87 and no difference. Changed the fuel filter, pcv valve and pcv filter and no change. I'm going to recheck the rotor tomorrow. I'm gonna start swapping ignition parts with my dads car and see what happens. I'm going to start with the blaster coil.

Roger Mabry

My Stang was doing the same thing...coil wire connection was loose - tightened
it with pliers and it has not missed since. Was especially bad going up a slight
hill...having the coil on the fender well and the long coil wire...

Konarider321

Checked the rotor and put on a new coil, still no dice. Napa know how wasn't any help either. I have no idea what to do now.

dawson1112

Does the check engine light come on? You should pull the codes and see what it has stored in the computer

mongolchuck

Is it a steady miss? If it is pull plug wires one at a time at the dist while running. If a particular cylinder is firing the miss will get worse when you disconnect the wire. If there is no change when a cylinder is disconnected that is your bad cylinder. Pull codes. Could be a bad o2 sensor as they start showing problems after the engine has warmed a little and gone into closed loop.

Konarider321

No CEL. I'm gonna try the paper clip trick.