Engine bogging down/hesitating

[Trefty]

I've got a 4.0L SOHC engine and when I first start it up in the morning it runs great, idles at about 900-1000 RPM and responds great. After a couple minutes the idle drops a bit to about 700RPM and it starts to rattle slightly, sometimes worse. It also hesitates at times while under load, I can put the gas all the way to the floor and it takes a few seconds to actually get going. To me it seems like it could be a sensor problem since it seems to be running fine from the start, but I'm not sure. I changed the plugs about 5,000 kms but didn't change the wires at the same time, could that be the issue? Also, changed the temp sensor, cleaned out the IAC and changed the intake gaskets.

 

[jlsparky7]

Might wanna clean your air intake and IAC (idles air control unit) Heres a vid I made that should help.

http://www.youtube.com/watch?v=VRciBxP5zB0

 

[celly]

I used to have a SOHC equipped Sport and same thing happened to me. That was before I found this site and I ended up taking it to a local Mr. Lube and paying for their "fuel system treatment". Worked like a charm. Had I known about "Seafoam" back then, I'm sure a good treatment with that would have done the trick.

Use "Seafoam" as a SEARCH term to check the archives of EF. There are plenty of threads on the SOHC. My preference is the "IAC" method. Others will tell you the Brake Booster method is OK, but it's fairly well established that you don't gets as good coverage doing it that way.

 

[Trefty]

I used to have a SOHC equipped Sport and same thing happened to me. That was before I found this site and I ended up taking it to a local Mr. Lube and paying for their "fuel system treatment". Worked like a charm. Had I known about "Seafoam" back then, I'm sure a good treatment with that would have done the trick.

Use "Seafoam" as a SEARCH term to check the archives of EF. There are plenty of threads on the SOHC. My preference is the "IAC" method. Others will tell you the Brake Booster method is OK, but it's fairly well established that you don't gets as good coverage doing it that way.

Thanks, I'll give that a try. Quick question, I checked out another thread about the IAC method and says something about pouring the seafoam into the t-connector on the IAC tube. On my engine the tube just goes into the air intake hose, do I just disconnect it there and the pour into the tube? Thanks.

 

[celly]

Thanks, I'll give that a try. Quick question, I checked out another thread about the IAC method and says something about pouring the seafoam into the t-connector on the IAC tube. On my engine the tube just goes into the air intake hose, do I just disconnect it there and the pour into the tube? Thanks.

Are you certain you have the SOHC? In your description, it says you have the XLS. Most XLS have the OHV engine (but I understand the odd one does have SOHC).

Sorry, I have a V8 now. I can't remember the configuration but there are surely tons of photos on the site of what you're looking for.

Good luck.

 

[Trefty]

Are you certain you have the SOHC? In your description, it says you have the XLS. Most XLS have the OHV engine (but I understand the odd one does have SOHC).

Sorry, I have a V8 now. I can't remember the configuration but there are surely tons of photos on the site of what you're looking for.

Good luck.

Yea I'm positive it's a SOHC. It's a rebuilt vehichle so that may be a reason for having XLS badges on it. Anyway, I checked a couple more threads and it seems that the first thread I looked at that showed a t-connector in the tube was just inserted in their to make pouring the seafoam easier. I'm gonna go get some and try this in the next couple days. Thanks again.

 

[Trefty]

I haven't performed the seafoam clean yet, but does anyone have an idea what could be causing the vehicle to idle beautifully at start up only to drop and start to "rumble" and shake after idling for a couple minutes? My guess is that it could be a sensor issue but not sure where to start? I've replaced the temp sensor thinking that might be it but that changed nothing. I cleaned out the IAC and that improved the cold temp starting but didn't affect the idle. I cleaned the MAF sensor and that didn't change anything either. Checked the PCV valve and that seemed to be working. Is there anything else to check? I changed the spark plugs about 5,000 kms ago but didn't change the wires, I'm sure they need to be changed but I would imagine if that was the problem it would affect the vehicle right from start up.

I'm sure the seafoam treatment will help the overall performance, I'm just wondering what is causing the RPM to drop after idling fine at startup?

 

[Trefty]

Ok, did the seafoam and it seems to have cleared up the hesitation a bit, but I'm still getting the rough idle after the vehicle has been running for a minute or so. Anyone have any idea what could be causing this? The other day the idle was starting to fluctuate from about 600-700 rpm down to about 350-400 and it felt like it was about to die. Doesn't do that very often but normally idles around 600-700 but as a "rumbling" feel to it, might just be my exhaust on that though.

 

[Trefty]

Anyone have any other ideas? FWIW, I also have a strong gas smell at times while it's idling. Could the EGR system be to blame? The thing that's stumping me is why it's idling great whenever I first start it up but always drops and the exhaust starts to rumble after around a minute of idling.

 

[sloop]

i would pull the codes - might give you some hints