Additive May Help with Annoying Transmission Shifts

Dear Doctor: My 2017 Toyota Tacoma TRD 2WD has an annoying shift problem. Toyota has added a torque converter to its newer Tacoma models and this may be contributing to the problem, as my older Tacoma shifted well. The shift problem is most noticeable when moderately accelerating; at about 35 mph the transmission shifts up, the rpm drops to about 1,400, and the truck jerks. The dealer has reloaded the software twice and replaced the converter, but with no improvement. Toyota engineers said it was shifting as designed. What should I do? Bob

Dear Bob: Automatic transmission shifting complaints are very common on a variety of vehicles. Shifting patterns are designed to maximize fuel economy. The torque converter has a lock-up mode and when it goes into lock-up there is no slippage between the engine and transmission. Reprogramming the ECU can sometimes make a noticeable difference. There are additives for the transmission that do change the fluid friction ability and offer a slight amount of slippage at converter lock-up. A transmission additive could be the solution for you.

Dear Doctor: I own a 2012 Nissan Pathfinder with 52,000 miles. I live in Pennsylvania and when I fill the tank the estimated “mileage to empty” reads 325 to 340 miles. But when I’m in New York and fill up, it indicates 275 to 285 miles to empty. This happens no matter which brand of gas I use. What’s going on? Charles

Dear Charles: Some filling station gas pumps will pump more fuel than others. I have no explanation on the miles-to-empty readings, only to say that it’s based on the fuel level sensor in the fuel tank that calculates the miles to empty.
Dear Doctor: I have a 1986 Chevy S-10 pickup truck with the 2.8-liter V-6 that’s been rebuilt a few times. It starts fine, but after being driven and turned off, it re-starts but doesn’t immediately throttle. After a few minutes it finally runs. What are your thoughts on this? Donnie

Dear Donnie: Fuel pressure and delivery are critical on an older vehicle, such as yours. The coolant temperature sensor and spark must be checked. I have seen cracked and missing fuel filter O-rings cause all kinds of problems. Fuel pressure regulators and throttle body injectors should also be checked.

Dear Doctor: I have a 2004 Volkswagen Touareg. A beeping display on the instrumentation panel states, “oil pressure stop engine check manual.” It’s a sporadic alarm that occurs randomly. A mechanic checked the oil pressure and said it’s fine. The dealer service tech drove the vehicle for about an hour and the alarm did not sound. What should I do next? Dennis

Dear Dennis: I would start with a factory oil pressure switch and correct factory oil filter. I have seen some partly blocked oil pickup screens. Removing the oil pan is a simple task and may be worth an inspection.

Dear Doctor: I own a 2003 Subaru Forester. Can I use Mystery Oil to remove sludge from the engine? If not, is there another product that will work? Can it be used between oil changes? What procedures should I follow? Stanford
Dear Stanford: I personally would not advise the use of any chemicals in the crankcase. I would recommend switching over to the use of full-synthetic oil — and use a quality filter, too.

Dear Doctor: I saw an advertisement for FixD. It’s an on-board connection plug-in device to diagnose car problems, such as “check engine.” It costs $59. What is your opinion? Michael

Dear Michael: Model-year 1996 vehicles and newer have a diagnostic system that uses a simple plug-in scan tool. Some companies also offer a small plug-in code reader that connects with a cellphone. Code reading scan tools start at under $100 and can also be used to clear codes shut off the check engine light.

— Junior Damato, Motor Matters

Copyright, Motor Matters, 2018

(Manufacturer photo: 2017 Toyota Tacoma TRD)

Junior Damato is an ASE-certified Master Technician.

E-mail questions for publication to

This entry was posted in Chevrolet, Get Your Car Fixed -- Ask the Auto Doctor, Nissan, Subaru, Toyota, Volkswagen. Bookmark the permalink.