While I'm driving down the road, the engine suddenly speeds up and then bogs
down. Sometimes it quits running. When it speeds up, I notice the
speedometer increase about 10 mph, but don't notice the vehicle actually
increase in speed. I have found some vacuum leaks, but the vacuum line going
to the transmission doesn't leak.
Thanks in advance for any help with this problem,
Check the engine grounds. Also have the battery checked. They can go bad and
allow a lot of engine noise which drives the computers crazy. Make sure
connections are clean and as I said all ground connections.
I replaced the battery and went for a drive to test the lockup torque
converter. I drove the van at 55 mph and depressed the brake just enough to
turn on the brake lights and felt and heard the downshift (engine rpm went
up a bit). When I let go of the brake I felt the up shift, but it was more
subtle. It was hard to concentrate because of the road noise and wind noise.
The engine did not bog down or mess up while I was doing this. Later last
night I was driving in the city and had just made a turn and was
accelerating and the engine bogged down and stalled. I had the transmission
selector in "D" instead of the "D" with the circle around it. This problem
is really intermittent.
The exercise you did at 55 mph demonstrates that the torque converter lock
up is working - at highway speeds. You're right - it's a fairly subtle
thing, but you should have been able to notice it on the tachometer (if your
van has a tach).
As for why it bogged and stalled in town, it's anybody's guess. Could be a
lot of things. The van really needs to be scanned as a starting point.
Anything else is just guessing and that will get costly in a hurry.
I got it scanned today and there were two codes. I don't remember the
numbers but one was EST (Electronic Spark Control) which the mechanic is
replacing my crankshaft sensor to repair. The other was Quad something which
refers to a circuit board under the dash. The mechanic said the quad
something controlled my transmission. He also said the crankshaft sensor is
probably causing the quad board to mess up. I hope he is right.
With the description of your problem that you posted Ken, nobody can tell
you that. It does sound torque converter related, but I sure would not jump
into replacing it at this point. Get the car scanned and see if there are
any codes. Step through from that point forward.
Picked the van up tonight and it is not fixed. $140 down the drain. Tomorrow
I will remove the coil packs to test them and see if I can get into the
ignition module underneath to test it. I knew I couldn't trust a mechanic to
This reminds me of the time my ex-wife had a problem with her car. It ran
bad when it was raining or damp. She took it to the same place and each time
they replaced something different. She ended up spending $340 on parts that
were not bad. When she told me about it I took a squirt bottle on a nice day
when the engine was running okay and started squirting different components.
When I squirted her coil her car ran bad because there was a crack in it.
Interesting point..... ( I've been burned there too )
The mechanic's done the work, installed the parts...
and the problem's not fixed.
What do you owe the shop ? Do they owe you a refund ?
In the medical field, even if the patient dies
the surgeon and the hospital still send a bill....
You are a more tolerant man than me Ken. I would have insisted on a labor
refund at the very least. I know that mechanics get away with this all of
the time, but that does not make it right. I can see covering the cost of
the part and he's got profit in that part, but he should have refunded the
labor for this. I'm not faulting his diagnosis, but when the problem is
clearly not repaired, it's not repaird.
I can troubleshoot to the component too Ken and it's frustrating today
because there are not schematics and so many things today are inputs to a
computer or triggered by one. Very complex and one would need logic flow
charts to troubleshoot it.
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