Stumped,suggestions?
Senior User
Joined: Apr 2005
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I would check the EGR circuit to see if it is stopped up with black stuff. The passages for the egr get plugged with black crap. Depending on the engine, sometimes you have to remove the intake to clean it properly. Other engines you can just pull the egr valve.
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Junior User
Joined: Aug 2003
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I would check the EGR circuit to see if it is stopped up with black stuff. The passages for the egr get plugged with black crap. Depending on the engine, sometimes you have to remove the intake to clean it properly. Other engines you can just pull the egr valve.
My intake cleaning consisted of pouring seafoam in the brake booster hose and also taking off the inlet tubes and spraying the TB with cleaner.
On a different note, when I replaced the spark plug wires two of the wires were barely long enough so they are stretched over the valve cover touching it on cylinder 5 and 6. It didn't make any difference in the rough idle after replacing the wires so I thought it was ok. Is it bad to have the wires touching the valve covers like that?
Postmaster
Joined: Aug 2004
Posts: 2,908
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From: West Mansfield, Ohio
It all depends on the type of wires and how tight they are against the valve cover. I had cheap wires on my ranger when had them run over my air breather tube (rubber), but I all of a sudden lost a cylinder. Got out and saw it arcing into the inside of the air tube (must have been metal inside)
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Junior User
Joined: Aug 2003
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After more searching on this site, it seems the problems I have could be related to the following sensors; EGR, MAP, IAC, TPS. The previous 2 mechanics said nothing came up faulty on their scopes so I take it those sensors would have been checked at that time. Is that safe to assume?
I have an appt with a 3rd mechanic tomorrow to see if he can find the problem since I think I am at the end of my ability. If he comes up with nothing then that might be the end of me seeking professional help.
I'll let you know what they say and hopefully they can find something usefull that might help someone else on this site. I''l keep you posted.
I have an appt with a 3rd mechanic tomorrow to see if he can find the problem since I think I am at the end of my ability. If he comes up with nothing then that might be the end of me seeking professional help.
I'll let you know what they say and hopefully they can find something usefull that might help someone else on this site. I''l keep you posted.
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Junior User
Joined: Aug 2003
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UPDATE:
Got truck back from mechanic, couple things were found.
Codes: 327, recommended replacing EGR position sensor
172, O2 sensor stuck lean, caused by bad A.I.R Diverter solenoid, recommended replacing A.I.R diverter solenoid
634, replace manual lever position sensor
He said none of these things would cause a rough idle. He said the "rolling idle" is being caused by lean/dirty injectors. Recommended removing and either cleaning or replacing injectors. This is similar to what the other guys were saying so I think I am going to replace the injectors.
Questions:
1)I know I need #19 injectors but was wondering if design II & III will both work in my application. Any recommendations?
2) Where exactly is the A.I.R diverter solenoid? I was looking for the part online and couldn't find it. Is it called something else? How hard to replace?
3) Is the MLPS sensor hard to replace and where is it located?
Got truck back from mechanic, couple things were found.
Codes: 327, recommended replacing EGR position sensor
172, O2 sensor stuck lean, caused by bad A.I.R Diverter solenoid, recommended replacing A.I.R diverter solenoid
634, replace manual lever position sensor
He said none of these things would cause a rough idle. He said the "rolling idle" is being caused by lean/dirty injectors. Recommended removing and either cleaning or replacing injectors. This is similar to what the other guys were saying so I think I am going to replace the injectors.
Questions:
1)I know I need #19 injectors but was wondering if design II & III will both work in my application. Any recommendations?
2) Where exactly is the A.I.R diverter solenoid? I was looking for the part online and couldn't find it. Is it called something else? How hard to replace?
3) Is the MLPS sensor hard to replace and where is it located?
Postmaster
Joined: Aug 2004
Posts: 2,908
Likes: 2
From: West Mansfield, Ohio
Ok first off I'd run a lot of injector cleaner through the tanks before you replace them. I've got 219,000 on my 351 runnin with cheap gas all the time and I've never had a problem with them.
I'm not sure about the AIR diverter sylenoid, but I think it is mounted close to the coil, with two vaccuum lines running into it (One runs to the egr). I THINK thats it, but not sure. It controls the opening and shutting of the EGR valve.
The MLPS is on the driver side of your tranny. Its the Manual Lever Position Sensor. It tells the computer what gear you have selected with your shifter. Pretty easy to replace.
I'm not sure about the AIR diverter sylenoid, but I think it is mounted close to the coil, with two vaccuum lines running into it (One runs to the egr). I THINK thats it, but not sure. It controls the opening and shutting of the EGR valve.
The MLPS is on the driver side of your tranny. Its the Manual Lever Position Sensor. It tells the computer what gear you have selected with your shifter. Pretty easy to replace.
Postmaster
Joined: Aug 2004
Posts: 2,908
Likes: 2
From: West Mansfield, Ohio
You are correct Tim. Not sure what I was thinking. I think it either pumps into the back of the heads or into the cat, but you were close enough
. Thanks for correcting me there.
. Thanks for correcting me there.
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Cross-Country
Joined: Oct 2005
Posts: 91
Likes: 1
I had a very similar problem with my 302 89 Ford F150. I had a miss/rough idle problem that would last until 1500 rpm.I did every thing attempting to find the problem. I finaly took it to Ford and they put the computer to it and drove it around with there computer hooked up to my computer on the truck. They then down loaded that information to FMC ( Dearborn) and they determined that the distributor was floating around from idle to approx 2000 rpm. Replaced the distributor and had no problem. Something to think about.
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
Originally Posted by 306
I had a very similar problem with my 302 89 Ford F150. I had a miss/rough idle problem that would last until 1500 rpm.I did every thing attempting to find the problem. I finaly took it to Ford and they put the computer to it and drove it around with there computer hooked up to my computer on the truck. They then down loaded that information to FMC ( Dearborn) and they determined that the distributor was floating around from idle to approx 2000 rpm. Replaced the distributor and had no problem. Something to think about.
Floating in a distributor usually means that the points are not making it back closed at high RPM. You are saying this happens at low RPM and of course you do not have any points in the newer distributor.
Cross-Country
Joined: Oct 2005
Posts: 91
Likes: 1
That is correct. The bushing was was slightly worn. It would allow the shaft to wobble. This in turn caused a slight miss which appeared to be completly random. It drove me crazy. Any way, put in a new distributor and the miss was no longer. I even kept the PIP trace they did and you could see the "randoness" of the miss jumping around from cylinder to cylinder.
By the way, thanks for clarifing the "floating" for me. You are correct, the distributor is not a piont setup. Stock electronic TFI style. Thanks.
By the way, thanks for clarifing the "floating" for me. You are correct, the distributor is not a piont setup. Stock electronic TFI style. Thanks.
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