Engine Idles rough/stumbles
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Engine Idles rough/stumbles
I have benn having idling problems with my F150 going on 6 months. I hope someone can tell me if i'm overlooking something. This is what i have done so far, replaced map, O2, evr sol., cleaned throttle body, tested ACT and ECT, tested tps, tested the thermactor system, replaced intake manifold gasket, tested egr valve, and replaced the IAC. Everything checked out ok so i brought it in to the Ford dealer, they couldn't find anything wrong except for the EEC-IV. (so they say). They wanted me to order one from them for $350cdn. Anyways, I got a replacement eec-iv from an '87 F150, replaced mine with it and the truck runs exactly the same, chokes and stumbles when i'm at a stop sign or red light. I think i've checked everything there is to check, does anyone have any suggestions? I would appreciate them
Thanks
Guy
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
Thanks
Guy
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
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Engine Idles rough/stumbles
Is it hard to start? Does it lack power? How many miles on it? You could have a clogged cat or leaky/clogged injectors. At idle the injectors need to open and close very fast, so if they are bad then it may only show-up at idle. To test the clogged cat theory, you need a vacuum gauge.
Good luck.
Randy
Good luck.
Randy
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Engine Idles rough/stumbles
[font size="1" color="#FF0000"]LAST EDITED ON 28-Jul-00 AT 03:04 PM (EST)[/font][p]It starts well, it has pretty good power when it kicks down (for a 4x4). It has 85000 miles on it and I don't believe the cat is plugged because there is a recent post with the procedure for testing and I got the same results as they did this morning. I checked the fuel injectors when I replaced the intake manifold gasket and they all seemed ok. Not one was different from the other, all looked clean. Fuel pressure is ok. I have the haynes manual, ford fuel injection manual and checked most sensors and replaced some. I am starting to believe it's a mechanical problem but what?
Thanks for your reply RGAZ
Oh yeah, the idle starts off by swinging up and down very little working it's way up to a huge swing. this takes approx. 30 seconds. I have to really press hard on the brake pedal. It's embarrassing when there are other cars around. Then the idle stays low and the engine sputters and spews black smoke from the tail pipe and it eventually fixes itself. This is usually the scenario but the times always vary.
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
Thanks for your reply RGAZ
Oh yeah, the idle starts off by swinging up and down very little working it's way up to a huge swing. this takes approx. 30 seconds. I have to really press hard on the brake pedal. It's embarrassing when there are other cars around. Then the idle stays low and the engine sputters and spews black smoke from the tail pipe and it eventually fixes itself. This is usually the scenario but the times always vary.
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
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Engine Idles rough/stumbles
Guy,
Was the idle bypass solenoid disassembled cleaned when the throttle body was cleaned? I had a surging idle problem on my '92 F-150, checked and changed many of the items that you did to no avail. Found a post on here about cleaning the idle bypass solenoid, and have had a smooth idle since.
John
Was the idle bypass solenoid disassembled cleaned when the throttle body was cleaned? I had a surging idle problem on my '92 F-150, checked and changed many of the items that you did to no avail. Found a post on here about cleaning the idle bypass solenoid, and have had a smooth idle since.
John
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Engine Idles rough/stumbles
[font size="1" color="#FF0000"]LAST EDITED ON 28-Jul-00 AT 07:40 PM (EST)[/font][p]Yeah, it's a whole new idle air control assembly. Solenoid and plunger, new gasket. Throttle body also has new gasket. I know the intake manifold doesn't leak either because i sprayed all around the gasket with WD-40 and noticed no idle change. Read this on a post here. Thanks though appreciate your feed back
Guy
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
Guy
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
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Engine Idles rough/stumbles
My 92 f-150 was doing the same thing your is doing. I replaced so many things like you have until I found out it was the MAP sensor. Fixed it right up. Try using one from a friends truck, if possible. Good luck
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Engine Idles rough/stumbles
I replaced it about 6 month's ago. I 'm really at a loss about this one, i've gone over the sensors and so has Ford(dealer) or so they say. I don't know where else to look and i'm too afraid to go to a garage after what Ford did or couldn't do. If Ford can't find a problem who can?
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
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Engine Idles rough/stumbles
What sensors haven't you replaced? Maybe a vacuum leak? This is the part when you really start to hate your truck! Trust me I know what your going through. I took my truck to a ford dealership and I think a bunch of young guys worked on it. It had a shifting problem that the ford dealership couldn't find with their computer but when I took it to the transmission place they said the tranny was OK but they found problems with the TP sensor?? Why couldn't the ford dealship find this??? Makes you wonder huh. Put a new TP sensor in and it worked fine. Sometimes I think the Dealerships are full of crap and we all should send our trucks to ShadeTree Mechanic!! I'll ask around to see if i can find any more info for you!
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Engine Idles rough/stumbles
[font size="1" color="#FF0000"]LAST EDITED ON 30-Jul-00 AT 01:22 AM (EST)[/font][p]Guy, the black smoke is a clue. So is the idle speed swinging wider and wider (sounds like the computer is trying to control idle speed using the IAC, but something else is going on messing it up). But just what is the big question. Black smoke means too rich, whether by too much gas injected, or intermittant ignition problems not firing some cylinders.
Were you ever able to check the fuel rail pressure WHILE it was having trouble? While in gear, so load is there like when stopped at a light. Use reverse if you don't trust the person at the wheel to hold it!
Were you ever able to check the fuel rail pressure WHILE it was having trouble? While in gear, so load is there like when stopped at a light. Use reverse if you don't trust the person at the wheel to hold it!
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Engine Idles rough/stumbles
Yeah 92 flareside you hit the nail on the head about hating my truck. The sensors I haven't replaced are the TPS, ECT, ACT and EVP sensors. I do know for a fact that it's not the EGR valve because i watched the valve stem while the problem accured and there is no mavement. I also went through and tested all vaccum lines with no results. Sensors checked out according to test procedures. I suppose the tests aren't always right either!
I never thought of checking the fuel pressure while this is happening. I'm off to buy a fuel pressure tester. I'll just leave it hooked up until the problem occurs again and then see if it is swinging. I'll post back later tonight with the results...
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
I never thought of checking the fuel pressure while this is happening. I'm off to buy a fuel pressure tester. I'll just leave it hooked up until the problem occurs again and then see if it is swinging. I'll post back later tonight with the results...
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
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Engine Idles rough/stumbles
Ok, I tested the fuel pressure and it is as follows:
Key on engine off ----- 40 psi
Engine idling --------- 32 psi
Engine idling in gear --34 psi
The pressure rises to 40 psi when I stomp on the gas both in park and in gear. The hesitation occured once while the pressure gage was connected and the pressure rose to 40 psi while the engine was stumbling and sputtering and returned to 34 psi after. with the test completed and the engine turned off, fuel press. gage still connected, pressure is maintained in the fuel line. Tested the regulator to see if it held vaccum and it did.
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
Key on engine off ----- 40 psi
Engine idling --------- 32 psi
Engine idling in gear --34 psi
The pressure rises to 40 psi when I stomp on the gas both in park and in gear. The hesitation occured once while the pressure gage was connected and the pressure rose to 40 psi while the engine was stumbling and sputtering and returned to 34 psi after. with the test completed and the engine turned off, fuel press. gage still connected, pressure is maintained in the fuel line. Tested the regulator to see if it held vaccum and it did.
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
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Engine Idles rough/stumbles
The very thing you are describing happened to my Grand Marquis and Town Car. In both cases, it was the EGR Position Sensor (EPS). Only $20 at Advance Auto. I see you have a K&N filter, have you tried cleaning the MAF sensor wires?
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Engine Idles rough/stumbles
It's speed density controlled, no MAF on the '92s. It does look like i'll have to replace the rest of the sensors one by one to figure this thing out or just live with it until I can get an other truck or a mechanic which I can trust.(that will be hard for me now after Ford dealer twice said they fixed the problem and it returned shortly after. I am the fool for going there a second time!!)
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
'92 F150 XL 4x4, 5.0L AOD, Headers, K&N Air Filter, 3.55 Gears, 31x10.5x15 Tires.
