'96 Probe problem noone can diagnose

I posted a question to this forum on May 27 titled “96 ford probe problem”. This is another question…adding on to the first one.

I took my Probe to another Auto Repair shop to have Diagnostics ran on it, and so far after having the car for over 4 days, they cannot find the problem. They said everything checks out and reads on the computer the way it should. They cannot find ANYTHING wrong with it. This is the second place that has told us this!! BUT there is a problem…it stalls out when I press the accelerator to drive the car!! I haven’t been able to drive my car in about a month!!

What would be wrong with it, that won’t show up on Diagnostics??? Please someone give me some help!!


Fuel problems don’t show up on diagnostics, such as low fuel pressure due to pump problems, plugged filter, pressure regulator, etc.

Wow, I thought everything would show up on a Diagnostics, and that’s why they charge so much to run one. But, they did say that they tested the fuel pressure and it was fine, and we recently changed the fuel filter.

Throttle position sensors and non-working engine computers just to name two. If the connectors are corroded, they won’t show up either. Some disconnections are also no-shows. The mechanic could find it but can’t possibly bill you for less than $600. They just don’t want to fight with you. AUTOTECH (useless but sometimes works) suggests that a vacuum leak could cause this. It can, but that is the only thing it suggests.

We have no way of knowing what they did as a “diagnostic”. It may have been something as empty as attaching a scan tool to it and looking for DTCs (Diagnostic Trouble Codes). There is a lot that a competent mechanic can do with a scan tool. There’s a lot that an incompetent mechanic can’t do with all of the greatest test equipment.
The fuel pressure needs to tested with the engine placed under load. A competent mechanic doesn’t need instructions on how to do that.
Several sensors need to be performance checked throughout their range: the idle air control valve may not be flowing correctly; the throttle position sensor may be producing voltage spikes, or have flat spots; the MAF sensor may be in error; the throttle plate may be sticking; etc.

OK…the shop called and said that they think they have found the problem!! They said that the distributor isn’t getting enough spark…something about the coil?? They said they reduced the fuel output, and it ran fine, because the more you reduce the fuel intake, it doesn’t require as much spark?? Does that sound right or did I say it all wrong?? lol Anyway, that distributor is brand new!! So, I called the auto parts store I got it from, and they said that they would replace it if it was bad! WHEW!!

If you get stuck with this problem look up (Google) for a local Dyno shop, they charge about $75 - 100 per session and are very cost effective for this type of elusive problem as opposed to getting nickel and dimed on ‘try this and see’ diagnostics.

Just FYI ~ A Dyno is a rolling road and replicates conditions as if the car is being driven. I use XX Tuning in East Hartford, if there’s a problem, they’ll find it guaranteed.

it will show up,if you know anything about fuel trims,and mapping.

if not take it to the dealer, it may not pop a code,(but if you have some knowledge,the scan tool will tell all.

you must be trained,and understand what is happening at any one time,and WHY.