93 Q45 stalls and engine stops starts up fine again

[andreah123]

i recently bought a 93 q45 and have had no problems with it so far. Then one day it started dying on me. it will start up just fine i always let it warm up first. i will push on the and when i hit about 20mph it cuts out. i throw it in neutral and it starts up fine and keeps going. then i noticed it does it most often when i am turning right and pushing on the gas. sometimes it does it when i am going 45mph also. i am stumped. got a new fuel filter and read an article on here on cleaning the maf. there were pics but i cant find them. i also read about listening in the trunk for a buzzing or humming noise and sure enough there is one so does this mean its the fuel pump? i need pics if anyone can help i would really appreicate it. thanks

[93jdirty']

Sounds like a fuel problem, is there gas in the tank? lol When my tank gets low it will cut out like that when turning because the gas sloshes around in the tank.

[Mr1der]

lemme slide this thread over to the Q section, they'll be better prepared to help you out as some of the Q owners seldom post beyond that forum.

[goody90q45]

Is the check engine light (CEL) coming on when the stalling happens? If no CEL and you're hearing buzzing in the trunk then it's probably the fuel pump. You need to change it soon before it takes out the fuel pump controller (FPCU), a pricey unit at about $700 from the stealership.

If you're getting a CEL then it could be intermittent failure of the Mass Air Flow Sensor (MAF) in which case you should be pulling codes from the ECU to help diagnose the problem.

Welcome to the Q45 forum.

[andreah123]

ya i thought it could've been that at first but i filled er up but with reg unleaded and it kept doing it. then i found out that your only supposed to use premium, oooops. so after running 4 full tanks of crap gas through the car i changed to premium. could that be the problem? its still doing it though

[Infinitiguy19]

Well if your knock sensors are running then no because they will prevent knocking.

And if they are bad then the timing is already retarded to prevent knocking.

So win win, But regular gas is bad overall for a Q or any other car you love.

[jimbyjimb]

Use the manufacturers reccomended fuel on stock cars. If it calls for regular, give it regular. New vehicles are very precision tuned, and are tuned to run best at the manufacturers reccomended fuel type. Higher octane regularly run in a vehicle, unmodified, designed to run on 87 is just as damaging if used regularly as 87 would be to a vehicle calling for 92+. Manufacturers typically have standards for a reason and, unless you are a fully educated automotive professional, going against manufacturers reccomendations is a fool's errand since you have no understanding of the causes of changing the conditions on which the vehicle is designed to perform best and longest under. Immediate savings may lead to unnecessary large repair costs in the future. Foresight will serve anyone well.

[Q45tech]

The problems arise from the knock sensor failure advance cure reduction vs rpm curve and the attack and release time of different knock profiles.

The ecu is constantly trying to advance the timing to gain MPG efficiency in every cruise situation and it assumes it is working with the most PREMIUM of fuels not the least.