1995 Q45t - Has the Herky Jerky Shakes

[dinovio]

When I am driving, usually around 60-62 mph, the car begins to have convulsions. Stalls from time to time at a red light, but not everyday, sometimes once a week, very frustrating, recently replaced the secondary throttle sensor because of this, my changing the sensor did not cause this, i also recently cleaned out the throttle body with carb cleaner. Please advise as to what other issues could be

[Window45]

TPS (throttle positionsing sensor) check it and clean that sucker... see if that might help out a bit? what's the RPM's when the cars ideling?

[dinovio]

revs are 500, i believe i cleaned that thing out already, i am new at this stuff as well

[Window45]

when the AC is on and your stoping does the rpm gauge ever bounce up and down.. even a little?

[dinovio]

have not been running ac, however, when i was the symptoms were the same

[Window45]

ooooo i know this sounds SUPER silly but go outside and have a look at your fan... check for a brken or wharped blade... maybe one with a piece missing.. im not the smartest when it comes to these things.. but never know

[Rex]

Has the fuel pump vere beenr epalced?Does it sound like a swarm of bees in the trunk?Has the fuel filter ever been replaced?What grade of gas are you using?MAF cleaned?

Need more maintenance back ground, but my first inclination is a fuel issue. Fill in some blanks for us, and we should be able to offer better advice.

[Window45]

lol i was at a light once, and i was missing two blades off my fan.. never knew what all that shaking was goin on.. but anyhoo.. a broken fan ended up costing me two belts, starter, waterpump, pully system, and a new fan, PLUs labor, all for about 1100 dollars... it can SUCKYYY

[dinovio]

fuel,pump was replaced about 3000 miles ago

[dinovio]

i don't know about MAF, I use regular gas, and I have never replaced fuel filter

[maxnix]

fuel,pump was replaced about 3000 miles ago

New O ring and fuel filter? Lines and tank inspected? No film or anything?

[Unnatural1]

You should be using premium fuel (91+ octane).

I guess the check engine light is not coming on when this happens?

When the fuel pump was replaced was the fuel pump control unit replace as well?

When the car dies while stopping is it usually AFTER you've been driving at highway speeds and slowing down? Or can it happen anytime?

If you can figure out what circumstances cause this problem and can then possibly replicate the problem at will, then it will be MUCH easier to diagnose.

[goody90q45]

Has the fuel pump vere beenr epalced?Does it sound like a swarm of bees in the trunk?Has the fuel filter ever been replaced?What grade of gas are you using?MAF cleaned?

Need more maintenance back ground, but my first inclination is a fuel issue. Fill in some blanks for us, and we should be able to offer better advice.

Dinovio- Most all of us are leaning towards a bad fuel pump/FPCU and I'll join the crowd also. More maintenance history (mileage?) would be a big help. Unfortunately it's an intermittent issue and is going to be hard to pin down. At some point you're going to have to put a fuel pressure gauge inline past the filter and see what's there. You need 35+ psi at idle and 43+ psi at speed.

I always suggest doing the easy and free things first looking for obvious problems so here's my suggestions. Start by looking to see if the fuel pump controller (FPCU) in the trunk shows signs of dying by looking at the connection. It's in the background in the pic and the connector is in the foreground with the clip on it. Are there any signs of charring, melting, burn through, etc.? If so your FPCU is shot.

You mentioned stalling at idle and not starving for fuel at speed so also take a look at the MAF connector and MAF pins. They need to be free of corrosion (no green) and lubed with dielectric grease. If you're seeing corrosion on the MAF connector chances are many others in the engine compartment look the same (i.e. TPS) and could use cleaning. The connector pins need to be tightened to look like the one in the middle and the connector when attached to the MAF should not wiggle. (Is it loose now?)

Checking both of these items is very simple, will take about 30 minutes, and is free. Let us know if you see some improvement.

[maxnix]

i don't know about MAF, I use regular gas, and I have never replaced fuel filter

You have a lot to learn and the first is change out all fluids and filters and only use a Ter 1 Premium fuel.

Try reading a few of the previous posts here in your spare time. It will help immensely.

The FSM is the bible of Q ownership. Read it also. Even the OM will help you.

http://www.nicoclub.com/FSM/Q45/

[tmak26b]

Right before my FPCU let go, I started experiencing random stalling and bucking and backfiring. Better start learning how to take apart the rear seat and rear shelf.