[watchdude1]

HI,
I have a 1988 Toyota pickup , I was driving to work at 55mph when my truck started to speed up on it's own, I pushed in the clutch (it is a 5 speed) and the engine revved to 8 grand, on it's own, I put it back into 5 gear and put the brakes on but it would not slow down, I had to shut off the car, Then I started it up again and it was still full throttle, I pulled over and checked the linkage it was fine. I started again and it was ok for 2 min then started to speed up again I hit the gas and it went back to normal. I am think in throttle sensor, which I changed 1 year ago because the Idle wasn't staying at 800rpm it would jump to 2000rpm and I would tap the gas pedal and it would go back down to 800rpm. or maybe Toyota has a computer problem with there new Toyota's and the older ones going back to the 1980s
Does anyone know what is causing this ?

[joe_padavano]

Originally Posted by watchdude1

HI,
I have a 1988 Toyota pickup , I was driving to work at 55mph when my truck started to speed up on it's own, I pushed in the clutch (it is a 5 speed) and the engine revved to 8 grand, on it's own, I put it back into 5 gear and put the brakes on but it would not slow down, I had to shut off the car, Then I started it up again and it was still full throttle, I pulled over and checked the linkage it was fine. I started again and it was ok for 2 min then started to speed up again I hit the gas and it went back to normal. I am think in throttle sensor, which I changed 1 year ago because the Idle wasn't staying at 800rpm it would jump to 2000rpm and I would tap the gas pedal and it would go back down to 800rpm. or maybe Toyota has a computer problem with there new Toyota's and the older ones going back to the 1980s
Does anyone know what is causing this ?

The newer Toyotas have electronic throttles, where there is no direct connection between the gas pedal and the throttle body. Your 88 precedes that and your problem is unrelated. More likely the throttle cable is worn and binding. It happens.

[chevelle_502]

I would try to get some graphite lube on the cable from where it comes out of the firewall to the bracket on the intake.

[joe_padavano]

Originally Posted by chevelle_502

I would try to get some graphite lube on the cable from where it comes out of the firewall to the bracket on the intake.

You can try that, but don't expect much. These cables are typically a multi-strand stainless cable inside a teflon-lined sheath. The failure mode is that the teflon wears out at the bends, the added friction causes one or more of the wires in the cable to fray, and the resulting sharp ends stick inside the sheath. No amount of lube will fix this, only replacement.

[watchdude1]

i guess I should get a new cable!! it seems ok but it is 20 years old
Why would the truck accelerate faster then what I was going if the cable just needed to be lubed it dosn't look fared can't tell how it is inside the covering though.
I was going 55mph took my foot off the gas pedal and the truck accelerated to 80 mph before I turned the key off.

[vettedreams2001]

I had the same issue on a 79 chevy luv, I had narrowed it down to a malfunctioning idle control solenoid, turns out it was shorting out and pushing the plunger all the way out, which in turn was acting like it was floored. Good thing the truck was so gutless it slowly started speeding up. Not sure if yours has one, but it's worth a shot.

[39 OLDROD]

I have been following this cars speeding up with peoples foot of the gas problem and for the life me can't see a truck or car doing this with a cable throttle. If its not computer related in some way. I will be the first to admit I know little about computer controls in cars BUT I AN'T NEVER had a throttle pull its self.And a floor mat would not make the peddle go down. It mite cause it to hang IF you had floored it or at lest accreted to blend in or some such. but seems to me that it would not get any faster then what you had pushed it down. Just my ramblings on this.

OLDROD
PS. Just a thought do you have cruise control?

[4 Jaw Chuck]

Is this the same truck with the mysterious brake pedal dropping to the floor syndrome and bucking issue?

Time to ditch that thing.

Seriously, is there a vacuum leak, dislodged throttle plate in the throttle body or stuck linkage? My guess is there is a vacuum leak between the throttle body and the engine or the idle air bypass solenoid is loose.

Since this truck has had an engine change there are a hundred things that could of been damaged in the swap including the intake system coming loose.

Time to spend some time under the hood and check all the basics before we blame Toyota for computer problems and unintended acceleration.

[watchdude1]

Originally Posted by 39 OLDROD

I have been following this cars speeding up with peoples foot of the gas problem and for the life me can't see a truck or car doing this with a cable throttle. If its not computer related in some way. I will be the first to admit I know little about computer controls in cars BUT I AN'T NEVER had a throttle pull its self.And a floor mat would not make the peddle go down. It mite cause it to hang IF you had floored it or at lest accreted to blend in or some such. but seems to me that it would not get any faster then what you had pushed it down. Just my ramblings on this.

OLDROD
PS. Just a thought do you have cruise control?

No cruise control, and I would not beleive it if it didn't happen to me, there is a throttle sensor, and the computer , that is all I can think of that could make the truck go faster, but not sure how they work, I thought a throttle sensor jus had to do with the idle?

[watchdude1]

Originally Posted by 4 Jaw Chuck

Is this the same truck with the mysterious brake pedal dropping to the floor syndrome and bucking issue?

Time to ditch that thing.

Seriously, is there a vacuum leak, dislodged throttle plate in the throttle body or stuck linkage? My guess is there is a vacuum leak between the throttle body and the engine or the idle air bypass solenoid is loose.

Since this truck has had an engine change there are a hundred things that could of been damaged in the swap including the intake system coming loose.

Time to spend some time under the hood and check all the basics before we blame Toyota for computer problems and unintended acceleration.

I drove it today and it ran good, I use it to plow my driveway, and i almost sold it last week,alot of people ask me if I want to sell it when I am just driving around. it still looks good. the brake problem was bad rear cylinders, the bucking was the spark plugs they were shot they only lasted about a year the tips were gone.

[39 OLDROD]

Originally Posted by watchdude1

No cruise control, and I would not beleive it if it didn't happen to me, there is a throttle sensor, and the computer , that is all I can think of that could make the truck go faster, but not sure how they work, I thought a throttle sensor jus had to do with the idle?

As I said don't know much about computer controls the reason for my question was I have heard of cruise controls acting up like that not to mention I am installing one(my first) and am hoping the advise I got from Dave and others keeps me from killing my self.

OLDROD

[T-bucket23]

If it is sucking air somewhere it can cause RPM run away.
Throttle position sensor should not cause this type of scenario.

[matt167]

look at the brake booster. I had a '92 ford Ranger 4x4, that liked to 'blow up' the check valve on the booster, and when it did, it had a 2-3k idle and it would cruise at 40 MPH in 3rd w/o any gas pedal. one time, it only cracked so it was intermittantly getting the high idle

[watchdude1]

I am going to go over the engine this week end and see what I can find,
thanks for the info!