302 shakes at low idle
 

ok so i got a 1991 ford f250 with a 302. as of a couple weeks ago it started running rough. also when im driving and it shifts into the next gear the whole truck will shake until it hits about 2000rpm and then run fine. when im parked and i pop the hood and give it a little throttle the whole motor shakes bad. i put in NEW: plugs, wires, cap, rotor, fuel pressure regulater, injectors, o2 sensor. check engine light comes on and it pulled a code 19 and 35. i took it to a shop and they said it was bad injectors and that didnt solve anything. any ideas?? im all out. i get terrible gas mileage and have ZERO power up hill. so the sooner i can fix it the better. thanks:-banghead!

double check your plug wires firing order. sounds like a couple might be on the incorrect plug. also pull the vacum line from the top of the FPR and see if it smells like fuel or if gas comes out. if so the fpr is bad and dumping large amounts of fuel. check your oil also to make sure there isnt any gas present.

curious what plugs are you using.

i just replaced the fpr. il double check the plug wires and check my oil real quick and post back what i find

Ok plug wires are correct. No gas outta the fpr. But oil does smell a little like gas and I changed the oil 386 miles ago and its already veryyy black

Just a few thoughts..

Be sure that #7 & #8 are routed away from one another. They are notorious for crossfiring.

Another thought is that there is too much fuel if you are correct with the oil change 386 miles and verry black. I had a similar problem with my 92 running rich and I checked the O2 sensor for correct operation. It was working but it lead me to other problems with the emissions system. Once I got that corrected, the shake and obvious rich condtion soon quit.

I thought of suggesting fuel injectors, but you said that they were replaced. If even one is not fully closing, you would get extra fuel and also terrible idling+driving problems. I did have a problem with a reman set of injectors and a 2nd reman set cleared it right up.

Also, I had a similar problem with my 300. Had old gas in it and I ran some marvel mystery oil in it at fill-up. You could also try Seafoam in the tank at a fill-up and also Seafoam the intake thru the Brake-Booster line and see if that helps any.

Let us know what you find.

was the injector wiring connected up correctly also? the efi system is speed density and is batch fired. if any of those injector wires are hooked up incorrectly it could also cause this.

I would put a fuel pressure regulator on there right away and get a reading. was the fpr you installed a stock unit or aftermarket.

They are hooked in right. Il try the spark plug wires 7&8 because I think they are zip tied together. Also il throw in seafoam in the places you said. Il let you know what I find

Also, what KemicalBurns stated about a fuel pressure regulator could have a definitive solution if it isn't stock. Also, if you could borrow, rent or purchase a Fuel Pressure Gauge, that would be a MUST-HAVE in diagnosising a fuel related problem. If there was an injector that was leaking(even new), a bad fuel pump, a kinked fuel line or a clogged fuel filter you could pin-point the problem simply to the fuel system itself and go from there.

And yes, 7 & 8 being ziptied together would now or soon, cause problems with cross-firing.

Look forward to hearing about your findings.

Ok so I moved 7&8 away from each other. Still does it. My fuel pressure is 38psi

Also was lookin at the egr valve. I looked threw the hols in it and reved the motor. It didn't move up. I also unhooked the sensor and vacuum hose and it ran the same. Reved it and what not and still ran like it does with it all plugged in. Just a thought. Any idea if that could cause this problem?

what type of spark plugs are you using?

check the timing with the spout connector removed. it should be at 10*btdc.

Im using autolite plugs. Il check timing when im get off work. Is the spout connector the one that plugs into the distributer?

its a small plug that is basicly just sitting there near the tfi module. make sure the motor is warmed up also. if you have a yellow crayon, rub it on the timing marks. this will help see where the timing is at with the timing light

Ok il let you know the results tonight

Timing is correct. Still have a code 19 showing up. What exactly is that?