Aerostar "stumble"
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Aerostar "stumble"
Gents. Posting here in hopes that one of you has successfully solved one of the two following problems.
The van is a 96 Aero, 4.0, AWD, 61K miles. Just bought it from a wholesale place so I have no real "history" on it.
First problem: If you gently touch the gas in drive, the van will "stumble" when it comes off idle. In normal driving, ie pulling away from a traffic light, you don't notice it because more pedal is used. But, if in bumper to bumper traffic, its pretty annoying. Have checked the TPS, that's not it. Happens both cold and hot. Ideas?
I've pulled the Idle Air Controller, and it looks OK and van idles fine without surging, etc. No trouble codes. ????
Second problem: and may not be a problem. I've got two of these vans... both identical except for years... the older one is a 91 Aero.
Here's the issue... the 96 is much "louder" under the hood than the 91. At idle, they're both equally quiet (except of course for the PS pump whine), but under power,the 96 is much louder. Almost sounds like there's no air cleaner... but there is. Its almost sounds like an intake "moan"... if you know what I mean. Ideas?
Thanks. KenP
The van is a 96 Aero, 4.0, AWD, 61K miles. Just bought it from a wholesale place so I have no real "history" on it.
First problem: If you gently touch the gas in drive, the van will "stumble" when it comes off idle. In normal driving, ie pulling away from a traffic light, you don't notice it because more pedal is used. But, if in bumper to bumper traffic, its pretty annoying. Have checked the TPS, that's not it. Happens both cold and hot. Ideas?
I've pulled the Idle Air Controller, and it looks OK and van idles fine without surging, etc. No trouble codes. ????
Second problem: and may not be a problem. I've got two of these vans... both identical except for years... the older one is a 91 Aero.
Here's the issue... the 96 is much "louder" under the hood than the 91. At idle, they're both equally quiet (except of course for the PS pump whine), but under power,the 96 is much louder. Almost sounds like there's no air cleaner... but there is. Its almost sounds like an intake "moan"... if you know what I mean. Ideas?
Thanks. KenP
FTE Community Team
Joined: Nov 2001
Posts: 1,865
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From: Oak Harbor, Washington
Aerostar "stumble"
>First problem: If you gently touch the gas in drive, the
>van will "stumble" when it comes off idle. In normal
>driving, ie pulling away from a traffic light, you don't
>notice it because more pedal is used. But, if in bumper to
>bumper traffic, its pretty annoying. Have checked the TPS,
>that's not it.
That sure sounds like the symptom of a bad TPS.
>Here's the issue... the 96 is much "louder" under the hood
>than the 91. At idle, they're both equally quiet (except of
>course for the PS pump whine), but under power,the 96 is
>much louder. Almost sounds like there's no air cleaner...
>but there is. Its almost sounds like an intake "moan"... if
>you know what I mean. Ideas?
Locked up fan clutch? With engine off, grab the fan with your hand and try to move it. Does it move freely, with just a little resistance? That's normal. If it grates or doesn't want to move, it's probably locked up. Fairly common problem. Left unrepaired, it'll eat your water pump, and possibly the radi_ator if the pump shaft breaks.
Regards,
Al S.
>van will "stumble" when it comes off idle. In normal
>driving, ie pulling away from a traffic light, you don't
>notice it because more pedal is used. But, if in bumper to
>bumper traffic, its pretty annoying. Have checked the TPS,
>that's not it.
That sure sounds like the symptom of a bad TPS.
>Here's the issue... the 96 is much "louder" under the hood
>than the 91. At idle, they're both equally quiet (except of
>course for the PS pump whine), but under power,the 96 is
>much louder. Almost sounds like there's no air cleaner...
>but there is. Its almost sounds like an intake "moan"... if
>you know what I mean. Ideas?
Locked up fan clutch? With engine off, grab the fan with your hand and try to move it. Does it move freely, with just a little resistance? That's normal. If it grates or doesn't want to move, it's probably locked up. Fairly common problem. Left unrepaired, it'll eat your water pump, and possibly the radi_ator if the pump shaft breaks.
Regards,
Al S.
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Aerostar "stumble"
Al, thanks for the note.
I've continued to experiment with the stumble problem... even tried to replace the TPS despite the fact it tested good.... but, not in stock and darn expensive. So, cleaned and lubed the idle air controller (IAC) and reinstalled with a fresh gasket (the old one looked less than good), moved the throttle plate stop screw 1/4 turn open, and did the best I could to clean the TPS with some "tuner/cleaner" used on noisy electronics switches. Drove it around and its MUCH improved. Hmmmm. We'll see.
Have checked the fan clutch and its OK. Even swapped it with the fan from my 91 just to be sure. That's not it. Have experimented and found the noise is engine load related, not RPM. I'm starting to wonder if there's a minor exhaust manifold leak... or a cracked manifold... that's today's task. I've tried plugging the exhaust to listen for leaks, but can't make the noise in my driveway... engine has to be under load.
Happy New Year.
Ken P
I've continued to experiment with the stumble problem... even tried to replace the TPS despite the fact it tested good.... but, not in stock and darn expensive. So, cleaned and lubed the idle air controller (IAC) and reinstalled with a fresh gasket (the old one looked less than good), moved the throttle plate stop screw 1/4 turn open, and did the best I could to clean the TPS with some "tuner/cleaner" used on noisy electronics switches. Drove it around and its MUCH improved. Hmmmm. We'll see.
Have checked the fan clutch and its OK. Even swapped it with the fan from my 91 just to be sure. That's not it. Have experimented and found the noise is engine load related, not RPM. I'm starting to wonder if there's a minor exhaust manifold leak... or a cracked manifold... that's today's task. I've tried plugging the exhaust to listen for leaks, but can't make the noise in my driveway... engine has to be under load.
Happy New Year.
Ken P
FTE Community Team
Joined: Nov 2001
Posts: 1,865
Likes: 273
From: Oak Harbor, Washington
Aerostar "stumble"
> . . . and did the
>best I could to clean the TPS with some "tuner/cleaner"
>used on noisy electronics switches. Drove it around and its
>MUCH improved.
Yup, I'm still putting my money on the TPS. If it's like mine, cleaning it made it work better for a couple of weeks, then it deteriorated again.
>Have experimented and found the noise is engine load
>related, not RPM. I'm starting to wonder if there's a minor
>exhaust manifold leak... or a cracked manifold... that's
>today's task. I've tried plugging the exhaust to listen for
>leaks, but can't make the noise in my driveway... engine has
>to be under load.
Failing motor mount could do that, too, if that's the case. Or, if you had a fairly severe lack of power under load (say, above 35 mph), and your noise was something like a hissing noise, I'd venture a catalytic converter that was plugging up.
Well, keep looking an posting, you'll find it.
HNY,
Al S.
>best I could to clean the TPS with some "tuner/cleaner"
>used on noisy electronics switches. Drove it around and its
>MUCH improved.
Yup, I'm still putting my money on the TPS. If it's like mine, cleaning it made it work better for a couple of weeks, then it deteriorated again.
>Have experimented and found the noise is engine load
>related, not RPM. I'm starting to wonder if there's a minor
>exhaust manifold leak... or a cracked manifold... that's
>today's task. I've tried plugging the exhaust to listen for
>leaks, but can't make the noise in my driveway... engine has
>to be under load.
Failing motor mount could do that, too, if that's the case. Or, if you had a fairly severe lack of power under load (say, above 35 mph), and your noise was something like a hissing noise, I'd venture a catalytic converter that was plugging up.
Well, keep looking an posting, you'll find it.
HNY,
Al S.
Senior User
Joined: Mar 2001
Posts: 403
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From: cincinnati hamilton
Aerostar "stumble"
just my two cents worth, but i would replace the in-line fuel filter too.( bottom of van, drivers side just aft of the motor)since you're unsure of its history, its worth a shot. rick
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Aerostar "stumble"
Well, after 6 months, I've finally fixed my "stumble"... posting solution here in case others are having the same problem.
Here's what I replaced in "the great chase"...
Idle Air Controller
Intake Temp Sensor
Throttle Position Sensor
Plug wires (twice!)
Plugs
Coil
Also, cleaned the MAF and throttle body.
Result? No change. Although the van ran better at higher speeds.
Turned out to be the Exhaust Gas Recirc Vacuum Valve. Mounted on the driver's side of the engine. Costs 20 bucks at the Ford dealer.
Mine leaked internally, allowing the EGR to lift a bit at idle... result was a vacuum leak and poor fuel mix.
KenP
Here's what I replaced in "the great chase"...
Idle Air Controller
Intake Temp Sensor
Throttle Position Sensor
Plug wires (twice!)
Plugs
Coil
Also, cleaned the MAF and throttle body.
Result? No change. Although the van ran better at higher speeds.
Turned out to be the Exhaust Gas Recirc Vacuum Valve. Mounted on the driver's side of the engine. Costs 20 bucks at the Ford dealer.
Mine leaked internally, allowing the EGR to lift a bit at idle... result was a vacuum leak and poor fuel mix.
KenP
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