1990 740 wagon has prolonged hesitation when I press accelerator before it will move forward. Cleaned fuel filter, added fresh gas, inspected plugs, but problem persists. Do you recognize problem, have a suggested solution? Thanks.

 

1990 740, is this a turbo or non-turbo, is it a Bosch LH2.4 or Regina or ?

I think I'd clean the throttle body, inspect all the vacuum and air hoses and replace or repair any looking even a little sketchy. verify the idle switch at the throttle is working properly.

a clogged fuel filter would affect high performance operation (like, full throttle at upper RPMs) long before it would have any impact coming off idle where the fuel usage is comparitively minimal... I'm curious how you cleaned the fuel filter, those are a replace-when-clogged item (which is very rarely unless you got some bad gas).

if this car is LH2.4 injection, does the onboard diagnostic box show any error codes? not all diag codes will light the 'check engine' light.

 

Transmission.

 

ahhhh, indeed, is this hesitation the engine revving up and not pulling? or is the engine stuttering and not revving?

if its the first, then check your ATF level. and if that ATF is black or smells burned, time for a flush/replace with some fresh stuff (I use Castrol Multi-Import Toyota-etc ATF in mine, as these AW7x automatic transmissions are in fact Toyota transmissions). also check the transmission control cable (often called the 'kickdown cable') at the throttle pulley for the proper amount of slack, and adjust if needed.

 

A failed throttle position sensor gave me the same symptoms.

 

Neither Bosch LH2.x or Regina has a throttle position sensor, just an idle (and in some configurations full throttle) switch.

 

Friends, thanks for the suggestions provided so far on my non-turbo 740. The mechanic in my remote small town suspects that the problem may be that the timing belt slipped a tooth or two off its mark when I started the car after it sat in yard and was not operated in cold climate from December to June. He thinks this may produce the hesitation that I initially described. Does this make sense to you as a reasonable possibility? Should we go to the trouble of seeing if this occurred, or should focus be elsewhere? Looking forward to your suggestions. Many thanks.

 

In Park, does the engine rev up freely? If so, no slipped belt.
If it sputters and lags, slipped belt is a possibility.