Engine noise help???

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Tom R

Active Member
Joined
Jul 20, 2003
Messages
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Location
Goose Creek, SC
Just had my 2003 XLT with 160,000 miles serviced and now have some idle and noise issues.



First off, what was done...

Brand New Platinum Spark Plugs, - Brand New Motorcraft Spark Plug Wires, - Oil change with Semi-Synthetic Oil (First time using a different brand than the one I always use, can't remember the brand, Castrol I believe and I always used Kendell GT1 Semi-Synthetic blend) and New oil filter, - Replaced Transmission Filter and pan gasket, - Changed Transmission fluid but didn't do the flush, - Replaced Front shocks with the Rancho 9000S again, - Installed New front sway bar links and bushings, - Front wheel bearings lubed, inspected and adjusted, - Installed New Fuel Filter, - Fuel induction and throttle body cleaning, Alignment Check and Tire rotation.



1st issue is at idle the engine kinda burbles or stumbles, it gets worse when stopped in traffic or at a stoplight. The rpm's drop to around 5-600rpms, then fluctuate up and down between there and about 1,000rpms. The longer it is stopped, the more it stays down around the 500rpm mark. When letting off the brake to start to drive forward, it usually stumbles, sometimes enough where I think the engine is going to stall, then it drives and accelerates without any hesitation or stumbles. The idle issue isn't real apparent when the engine is cold, but as it comes up to operating temperature it gets worse.



2nd issue is something that has appeared since I picked my ST up and I never noticed before is that there is now a clickity-click rattle sound when accelerating, almost as if the engine sounds like it has bad gas and is detonating, but that is definitely not what it is doing. If driving as a normal person would without "getting on it", the sound diminishes after getting up to speed. Now if you drive it like you have a lead foot, the sound is noticeably there when you put the engine under a load.



We have rechecked all plugs and wire connections, all intake air path and electrical connectors. All is ok and doesn't change the issues.



Help! Thoughts, ideas?



Thanks!
 
Have you cleaned your Idle Control Valve? See Projects section. As for the rattle when accelerating, it's either detonation or mechanical. Oil brand shouldn't make a difference.
 
Have you cleaned your Idle Control Valve? See Projects section. As for the rattle when accelerating, it's either detonation or mechanical. Oil brand shouldn't make a difference.
 
Still haven't resolved the issue. Ford dealer wants 25+ hrs of labor to change the timing belts and tensioners and that's before adding in the parts cost.



They did clean the entire fuel intake system including the Idle Control Valve. I took it to another auto shop that I know does the repairs on the 4.0L V6 timing issues. Owner and head mechanic listened to the engine in park as the rev it up and down, there is no noticeable noise that they can tell. Both of them say it isn't timing chain issues. I had the owner drive it so he could hear what I was hearing. He finally heard it and now he thinks it is timing chain related.



He wants me to bring it back so his head mechanic can drive it and listen to the engine to verify that. His mechanic thought it is a fan belt pulley bearing somewhere, but he hasn't driven it yet, he only heard the engine run in park. I didn't have time to leave the truck with them the other day.



The owner asked about the weight of the new oil used vs. the old stuff I have been using for 10 years. I assume the line of reasoning is that a less or more viscocity oil would affect the springiness of the tensioners against the chain???



He did suggest I go back to my normal place for oil changes and have them drain the new oil and change the filter and fill it back with my normal oil. I decided $40.00 would be an easy out "if" that was the issue. It wasn't, the same noise and issues are still present.



So, I'm off to take it back and let their head mechanic drive and listen to it. Owner did say if it was timing chain stuff, I could count on about $2500.00 to repair it. Matter of fact, he had one 4.0L V6 on the shop floor and they were changing timing belts and stuff on it.
 
Tom,

The oil change folks usually get there oil from drums. They might of mismarked a drum or, they thought your ford used 5w-20, many fords do nowdays. Make sure they use 5-30.

For the IAC cleaning, at 160K miles you might need to replace it. I had to on my Moms '01 grand marquis at 105K miles. 2 cleanings' didnt fix it.

Good luck
 
Thanks for the replies. Making progress, we found the source of the rattle... seems the two catalytic converters on the "Y" pipe coming off of the headers have disintegrated on the insides and a lot of that honeycomb material wound up accumulating in the 3rd cat body with some bigger chunks rattling around. Reving the engine up while the truck was raised in the air on a lift made it easier to track down. That cost me a little over $1250.00 to repair, much better than a timing chain changeout.



The stumbling engine burble rpm fluctuation is still present though. I'm gonna go back and clean the entire air / fuel intake path components, especially the IAC valve myself and see if that corrects it, if not, a new IAC valve is like $75.00. The shop I had do the original cleaning and work, I've known the owner for 20+ years and trust him, but I'm sure he as the owner probably had some junior tech do the work. Now that I think of it, when I got home and it was having the issue, I opened the hood to check some things out, noticed my 4.0L cover was missing. Called the shop, yep, It was left on the bench.



Got to spend quite a bit of time looking under the vehicle today inspecting everything while they were removing the cat components. My body mount bushings are dried out and about the consistency of a cupcake, touch them and they disintegrate. The 2nd shops says the can change them out for about $550.00, so I gotta do some research that. Read several horror stories about DIY and stopping the bottom disc from spinning while removing the bolts.
 
Have you cleaned your Idle Control Valve? See Projects section. As for the rattle when accelerating, it's either detonation or mechanical. Oil brand shouldn't make a difference.
 
Vic, the rattle was fixed, it was the catalytic converters disintegrating. That issue is fixed. The idle fluctuation is still a problem.



I paid the shop to clean the entire air intake path, fuel induction and components including the MAF, the Throttle Body and the IAC. After looking at it again today, the bolts for the IAC still have a build up of dirt and stuff on the heads and look like they were never even touched.



I'm going to clean the MAF again myself and take out the IAC and clean it to see if that fixes the stumbling issue. It's weird, it only occurs after the truck gets up to operating temperature and it doesn't do it if it is a cold start. One of the forums, a guy said he was tracking down the same exact issue and once the truck got warm, a rubber elbow warmed up enough to let in excess air or cause a vacuum leak.



If the cleaning doesn't do it, I guess I'll be chasing gremlins until I find it.
 
Have you cleaned your Idle Control Valve? See Projects section. As for the rattle when accelerating, it's either detonation or mechanical. Oil brand shouldn't make a difference.
 
Finally got it all resolved. The IAC was dirty, but not the culprit of the rough idle.



Cleaned the MAF, Throttle Body and IAC. Fired up the engine and now it was idling at about 2500rpms??? Stumbling problem was still there. Then I was really scratching my head and shut the engine off and let it cool down. A couple of hours later I examined every hose and coupling I could find with the engine still off, no luck.



Fired up the engine, rpm were about 2200rpms, and I let the engine come back up to operating temperature, then the stumbling started back in. I was rolling the throttle cam to rev the engine and noticed an elbow hose that was collapsed in on itself at the outer curve. pulled it off and the engine immediately died. Had a heavier duty hose elbow in the garage, so I replaced the bad one. Fired the engine back up, stumbling issue had gone away, but the rpms are still a little high. I'll let the computer relearn itself and then adjust the idle back down a little. Drove the truck in stop and go for a bout 20 minutes, no issue now.



The yellow piece of tape is where the hose collapses in on itself from the vacuum pull.

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My IAC before cleaning it, was definitely dirty from 161,000 miles on it.

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Saw that post on the forums a couple weeks ago, not really my issue & I ruled it out after previous examinations of the elbow didn't show any cracks or any other hoses with leaks. Plus, my truck wasn't throwing any codes. The one on the forum had a split that opened up once warm and they were getting error codes.



My issue only appeared once the engine got warm. Inspection of that elbow when the truck was cold didn't show any problem, but when warm and idling, thats when it was noticeable.



It wasn't a vacuum leak, but a closed hose not allowing the vacuum to be effective in the rest of the engine.



 
That's why Heater hose can not be used for vacuum....



Need to install Proper materials.



Todd Z



 
The hose that was at fault was an original stock oem elbow hose.



What you see in the picture above is a temporary troubleshooting fix to see if it corrected the problem. Haven't gone by the Ford dealer to get the "proper' one yet.
 
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