Rough idle

[killj0y]

Ok so today street I left work the second stop I came to the truck started running rough like a misfire. Fuel filter it's good it's new and I checked it anyways. Pump I can hear.

Wires I replaced last year. Maf checks out. Otherwise any ideas, I'm gonna check for codes and the plugs tomorrow.

 

[RonD]

Did the misfire go away when you started driving after the stop?

Is the misfire only there when engine is cold?

 

[killj0y]

No still there, and constant with acceleration.

 

[killj0y]

Anyone else?

 

[PanamaExpat]

Look to see if any plug wires have come loose. Happened to me more than once.

 

[RonD]

My '94 4.0 was starting to misfire, and it would come and go.
But the "come" was was getting more often than the "go", lol.

Changed original fuel filter, did seafoam in tank for injectors, new air cleaner(what the heck), didn't help anything, although it probably helped long term, lol.

Got a new set of plugs and plug wires(had original wires), and its like a new truck.
Never expected that, just figured after 18 years might as well change them, but was very happy with the results.

 

[killj0y]

Well checked the codes it spit out
P0401- egr flow insufficient detected

P1443- very small or no purge flow condition

P0301- cylinder one misfire

Clearly the misfire is obvious lol.

Let's see its got a new air filter, wires less than a year old, same for the fuel filter.
Maf and icv get cleaned regularly. Disconnected the maf and it ran the same.
I run fuel system cleaner every so often.
Haven't found any vacuum leaks. Should I bother pulling the plugs, they are kind of a hassle to get to. Besides is it common for a plug to go bad literally instantly? Like I said it had been running perfect no codes or hiccups.
Also I did check the wires and they are on there good.

 

[killj0y]

Man where's adsm...

 

[killj0y]

Any tips? :banghead:

 

[mitch4x4]

Does your egr have any leaks? I know I had a small crack in the tube to the egr on one of my old rangers and it caused it to act very strange, start up fine then just die with no warning. Or stumble at an idle etc. Also a plug can foul at anytime.

 

[killj0y]

Does your egr have any leaks? I know I had a small crack in the tube to the egr on one of my old rangers and it caused it to act very strange, start up fine then just die with no warning. Or stumble at an idle etc. Also a plug can foul at anytime.

Visually I don't see any, will spraying it with carb cleaner change the idle?

 

[killj0y]

Ok so removed and cleaned the maf and icv. Checked the cylinder one plug, no fouling or any sign of damage or irregular burning, that I could tell anyways. Air filter is clean. Also sprayed down the throttle body well.

After this she runs a tiny bit better but not much. While running unplugging the maf causes it to bog down a few seconds then returns to running the way it was. Unplugging the dpfe does nothing. Unplugging the icv causes it to almost die.

I also sprayed down most of the vacuum hoses I could see and no response. Same goes for the egr, plug 1, and a few other places.

How can I test the dpfe? And I can't see the screws holding it down any idea on type and size?

Also the plugs and wires are on good but it seems tue harness going to the rear and lowermost coil pack swings up and down a bit like the plastic broke but its still on there. Should I be concerned or its probably nothing?

Any other sensors or things I should suspect?

 

[Mike92STX]

I had a older Ranger that did that and it was a bad spark plug wire. The wire had broken in the shielding, they were the carbon wires not the old real copper wires. I had some bad gas that caused a car to run like that till I ran out the gas and put fresh in, usually it is water.

 

[killj0y]

I had a older Ranger that did that and it was a bad spark plug wire. The wire had broken in the shielding, they were the carbon wires not the old real copper wires. I had some bad gas that caused a car to run like that till I ran out the gas and put fresh in, usually it is water.

Well I'm gonna try ruling out the coil pack, wire and plug tomorrow. Also it starting running rough BEFORE gassing up, which at first I took to be it was running out since I was low. I know the gauge isn't always accurate on older rangers. after new gas no change. I gassed up at a reputable station where I've had no problems in the past.

 

[OREGANO_RANGER]

Rough idle- fix

Sup guys... Replaced the pcv valve on my 98 4.0 and rough idle is a thing of the past... $ 1.99 at o'rileys.