Surges/rough idle

Supernaut454 · #1 06-04-2011, 12:16 PM

My ranger has a surging at highway speeds....like it isn't getting enough fuel....or maybe too much? It also has a piss poor idle...

Parts replaced:

TPS
IACV
ECT
Plugs/wires
Fuel Filter
Ran seafoam through the fuel system (probably wan't a great idea as the truck ran better prior to doing this).

I am heading down to a buddies house tomorrow to run a fuel pressure test...any other ideas/stuff I should check into??

SpitfireEMT · #2 06-04-2011, 12:49 PM

Double check plug gap. Also make sure you have good fuel pressure. Pull your air filter and see if it runs smoother without it, if it does, replace it.

Supernaut454 · #3 06-05-2011, 08:21 AM

Checked the plug gap when I put the new ones in and the air filter is new though it is a garbage Fram filter. I think it is the high pressure pump.

littleblue · #4 06-05-2011, 09:05 AM

I had a 90 bronco II with 2.9 with the same problem. It would even throw a cel indicating a ignition problem and then a few miles later it would be fine. I replaced everything you have plus some, including new fuel pressure regulator, ignition module and checked for vacuum leaks. Ended up being the o2 sensor.

Jimmeh · #5 06-05-2011, 09:08 AM

I'm gonna say either O2 or MAF. Most likely O2, though. IIRC, they are only about $40 for the 2nd gens, but I'm not positive on that.

Psychopete · #6 06-05-2011, 12:53 PM

He will have a map sensor, no MAF. Pull codes and go from there. No check engine light to let you know when the computer sees something out of range or a faulty circuit. Could be anything from a vacuum leak to a bad sensor. Problems in EFI systems can get complicated, that is why the self tests are there - to help you narrow down what it is.

Jimmeh · #7 06-05-2011, 04:36 PM

Quote:

Originally Posted by Psychopete

He will have a map sensor, no MAF. Pull codes and go from there. No check engine light to let you know when the computer sees something out of range or a faulty circuit. Could be anything from a vacuum leak to a bad sensor. Problems in EFI systems can get complicated, that is why the self tests are there - to help you narrow down what it is.

DOH! Didn't even look at the year, lol.

Supernaut454 · #8 06-05-2011, 08:32 PM

Well it turned out to be a fouled plug. I am always good checking the gap....but somehow one slipped past. I felt stupid as hell....but whatever, the truck drives awesome now!