Rough idle

[My94Explorer]

I have a 94 Explorer XLT with a 5 speed manual transmission that I bought new in 94. It just turned 130k. I replaced the plugs at 100k. In the last year I have replaced the EGR valve and the unit that controls it for a CEL issue. Recently, I have had a problem with it idling rough on start up occasionally only after I have driven it around, shut it off for a bit, and then getting in and starting it again. It doesn't happen when the engine is cold and only idles rough on the initial start. I csn goose the throttle a bit to get it running ok and then it's fine. No problems at stops or anything. I thought that it might have been the fuel filter so I recently replaced it, but that didn't help. Have any of you experienced a similar problem? Thanks for any help.

 

[94Sport5]

I'd start by cleaning your MAF sensor and gently cleaning your throttle body. That should certainly make a difference if you haven't done so yet. Maybe run a seafoam treatment through the vacuum underneath the throttle body while holding the engine rpm at around 1800 to help clean the top end of carbon, it helps every time I do it!

 

[My94Explorer]

I'd start by cleaning your MAF sensor and gently cleaning your throttle body. That should certainly make a difference if you haven't done so yet. Maybe run a seafoam treatment through the vacuum underneath the throttle body while holding the engine rpm at around 1800 to help clean the top end of carbon, it helps every time I do it!

Thank you 94Sport5. I'll give that a try. When you say, "gently cleaning the throttle body" are you referring to using a TB cleaning spray from an auto parts store or removing the TB and cleaning it mechanically? I love Seafoam. I've used it a number of times with good results.

 

[94Sport5]

Thank you 94Sport5. I'll give that a try. When you say, "gently cleaning the throttle body" are you referring to using a TB cleaning spray from an auto parts store or removing the TB and cleaning it mechanically? I love Seafoam. I've used it a number of times with good results.

There's supposedly a special film on the TB plate that you're not supposed to scratch off, but I have done it several times with no I'll effects, it only helps! I would just spray the heck out of it and try to get the back side of the plate also!

 

[My94Explorer]

There's supposedly a special film on the TB plate that you're not supposed to scratch off, but I have done it several times with no I'll effects, it only helps! I would just spray the heck out of it and try to get the back side of the plate also!

There's supposedly a special film on the TB plate that you're not supposed to scratch off, but I have done it several times with no I'll effects, it only helps! I would just spray the heck out of it and try to get the back side of the plate also!

I read something similar about that on a Nissan forum when I was troubleshooting a problem on my Frontier. Thanks again for the reply.

 

[mcfixstuff]

Had a similar issue along with a bunch of other issues. All of my symptoms, including that, went away when I fixed the frayed, exposed wiring harness by my charcoal canister.

 

[My94Explorer]

Had a similar issue along with a bunch of other issues. All of my symptoms, including that, went away when I fixed the frayed, exposed wiring harness by my charcoal canister.

What portion of the harness was damaged? Was it close to the canister? Was it chafing on the body or somewhere on the engine?

 

[mcfixstuff]

What portion of the harness was damaged? Was it close to the canister? Was it chafing on the body or somewhere on the engine?

It looked chemically melted. Visually inspect all the wires that secure on the driver side wheel well. Look for exposed copper. Mine was pretty obvious once I visually inspected the harness's in the area.

 

[My94Explorer]

It looked chemically melted. Visually inspect all the wires that secure on the driver side wheel well. Look for exposed copper. Mine was pretty obvious once I visually inspected the harness's in the area.

View attachment 342051View attachment 342052

Wow! That thing was a mess. I took a quick look at mine today and didn't see anything, but I plan to do a better inspection in the next few days.

 

[kmack]

Classic symptoms of a bad ECT sensor (engine coolant temp).
Warm engine shudders and runs rough at startup.

Post #11 on this thread explains the why.

 

[My94Explorer]

Classic symptoms of a bad ECT sensor (engine coolant temp).
Warm engine shudders and runs rough at startup.

Post #11 on this thread explains the why.

Thank you for the heads up.

 

[Alfredroy]

I have a 94 Explorer XLT with a 5 speed manual transmission that I bought new in 94. It just turned 130k. I replaced the plugs at 100k. In the last year I have replaced the EGR valve and the unit that controls it for a CEL issue. Recently, I have had a problem with it idling rough on start up occasionally only after I have driven it around, shut it off for a bit, and then getting in and starting it again. It doesn't happen when the engine is cold and only idles rough on the initial start. I csn goose the throttle a bit to get it running ok and then it's fine. No problems at stops or anything. I thought that it might have been the fuel filter so I recently replaced it, but that didn't help. Have any of you experienced a similar problem? Thanks for any help.

yes i have and looking at fuel pump relay then injectors then check valve - also then fuel pump and filter if not solved with first three listed