94Q45 stalls under hard braking

[PalmerWMD]

Like the title says My cars stalls under hard braking,sometimes the electrical just seems to shut off for a split second ( radio stops tach speede etc shut off) but sometimes it goes all the way to the engine shutting off.

Also I seem to hear a very light hiss sometimes like a vacuum leak.

Fred..

[elwesso]

Fred in all the Q ive seen Ive always seemed to hear a slight hiss from the engine...

How's your fuel pressure.. I noticed when Ive seen your Q you always seem to have low fuel Hope you didnt fry a fuel pump...

I checked the FSM and basically it said to check FUEL PRESSURE, the IAC for correct operation, clogging etc.....

I assume you know you dont have a bad injector or something like that...

[3Q Jay]

Fred, you put it as during HARD braking. is the engine at Idle revs or some intermediate 'spool down' state. if at low idle and there is any sign of engine roughness, I'd look toward the vacuum brake booster.

[Q45tech]

Radio goes off? gauges drop.........electrical loose somewhere

[AZhitman]

I'll bet it has to do with the relocated battery....

[3Q Jay]

oops, i missed the part about radio and speedo cutting. i rescind on the vac brake booster, and would go electrical.

[Chally]

Sounds like a battery falling over, but I'm sure you'd have that tied down correctly...

Maybe it's braking that hard, all the electrons compress to the front & leave the rear with none... ha ha ha

[elwesso]

LOL # chally..

So that means under hard acceleration it gets really bright because they all rush back.....

[SFBayQ45]

Like the title says My cars stalls under hard braking,sometimes the electrical just seems to shut off for a split second ( radio stops tach speede etc shut off) but sometimes it goes all the way to the engine shutting off.

Also I seem to hear a very light hiss sometimes like a vacuum leak.

Did you find the answer to your problem Fred?

I just recently noticed a similar problem on mine. Under hard braking, the engine seems to want to shut off but doesn't. Then I feel a hard kick back from the engine as a result of the sudden stop...is that normal? It doesn't feel good at all, but I've never stopped hard before until this morning and noticed the problem. After experiencing that strange phenomenon, I decided to replicate the problem...unfortunately, I'm able to confirm that yes I get the same scary kick-back result everytime I step on the brake hard. Could some mount be loose (ie. trans mount, engine mount, etc.)?

[natsoundup]

I experienced this a couple of times in the 94 (sort of scared me)..... I think it may have been a build up of some crud.... hasn't happened in a couple of months.

I am about due for another can of BG44k.... I think that helped solve the problem.

[Chally]

Hiss, Vacuum leak? Have you checked your brake booster?I haven't experienced this on my Q, BUT, on some vehicles, when the revs get too low, the electrics momentaririly cut out which can affect the radio. All the dash lights will come on because the alternator is going too slow to charge.

Without an experienced technician checking it out, & hearing what's going on etc, then it may be difficult to diagnose over the web.

[hoju1301]

I had this problem a few weeks ago, it was low transmission fluid by two quarts! check the transmission fluid volume inside the transmission. The tech said theres also a FSB/TSB for this issue.