Good morning to all, can somebody teach me how to adjust the pressure limits on a MQ3-45, its on 60psi I need to reduce it, it is possible?

The air/fuel ratio that is capable of burning in an engine is fairly limited - too lean and the engine won't start and won't run, too rich and an engine will probably start but won't run smoothly and will soon choke and stop.
A cold engine needs a richer than normal mixture and acceleration also needs more fuel but unless a hot engine receives the right amount it won't run smoothly or reliably.

The useful life of a fuel injector is fairly limited and it is downhill after 70/80,000 miles. In the case of bad running, reduced power or excess fuel consumption it is best to check the fuel pressure and delivery volume and pull the fuel injectors for testing before moving on to other checks and adjustments.

Nearly all the things that could limit the maximum revs of a mechanical unintentional nature would probably cause the power to reduce as the maximum rpm is neared so acceleration would similarly reduce and if climbing a hill the maximum would never be reached.

If your description is accurate and the engine produces normal power to 3800 without tapering and won't go any further it is something only electronic rpm limiting is capable of rather than the usual culprits of strangled intake, strangled exhaust, insufficient fuel or timing problems. Sometimes it was something as simple as the throttle butterfly not opening fully.

Checking the injectors is only half the testing the fuel system should have - the fuel pressure and delivery volume and regulator function needs to be checked.

Opel once made an engine of 1.4 litre and over time it was stretched to 2.0 litres and beyond. That engine pulled strongly until it reached a ceiling of about 5400 rpm, less for a high mileage model. It was impossible to make the intake ports large enough or to maintain a sensible shape to the ports which made the rpm self limiting and was my only experience of what you describe in over 40 years. In all other cases of limited rpm the power always tapered because of external faults.

The regulator reduces fuel pressure at idle. When deactivated, your fuel pressure will be high, possibly reducing fuel efficiency due to rich operation. You should install a new regulator when possible.

check transmission fluid level.if transmission fluid level okay have vechicle code scan look for faulty transmission fluid pressure switch or faulty transmission range switch.faulty transmission control module.if all is good make sure transmission manual shift linkage not out of adjustment or shift cable broken if all is good possible transmission just failed.

usually an indicator of either a loss of pressure due to low fluid and/or air in the system (brake fluid leak) or extremely worn rear brakes (if drum brakes in rear). possible causes include master cylinder (internal fluid pressure leak), external fluid leaks (calipers, lines, wheel cylinders), rear drum brakes extremely worn down or severely out of adjustment. normally worn disc brakes may reduce pedal height SOME, but seldom "to floor". but the "mushy" quote combined with the "floor" quote suggests a hydrolic fluid pressure problem.

Well I'll tell you my situation and what worked for me. I was headed off to work one day in the morning when the reduced engine power light came on and my top speed became limited to15- 20 mph. I flipped a u and parked in my carport. I did some research online and found too options,. Some say to get the throttle cable looked @ by a dealer, while other suggested cleaning the leads on my battery. I did the latter using a wire brush (I really got in there) and it worked like a champ!. I'd try that out first. Good Luck

several possible causes for a soft brake pedal.

One is that the back brakes are probably drum brakes, and they need to be adjusted properly in order to reduce the distance from the shoes to the drum.

Another is that the master cylinder could be leaking fluid back into the reservoir when it should be pushing fluid to the wheels under pressure.

If you have opened and replaced any of the hydraulic system, there could be air in the system that needs to be bled out.

You could also have a bad power brake booster, that would make the pedal had and cause the engine idle to change when you hit the brakes.

adjust idle

may have water in fuel you can get a can of stuff that will help if it is water also[ octane 104 ]is very good

check your oil for low level or you probably
need valve adjustment