I have a 90 Z24 3.1.The car will start fine, idle fine. but when i have it in nutreul and coast down my driveway 15-30degree incline and hit the brake or change angle it will sputter and stall. get on the road and will drive fine for about a quater mile then when you go to stop it will sputter and stall. then it will buck and stall like mad after that. yet it will always start right back up sometimes shutting down right after word. I have checked the feul pressure and it is fine. I replaced the IAC valve, PCV valve, cleaned the Throttle Body, Plenum,cleaned the EGR valve, replaced vacume line to the brake booster, put in a new fuel filter, plugs and wires, cleaned the O2 sensor. Put a higher idle on still did it(uasually runs at or around 800-1000 rpm) took it to 1500 but no joy. what else could it be?? possibly the MAF sensor,TPS or is it dealing with the brakes can't find or here any vacume leak, it is a manual trans. The coil pack seems fine considering it starts and idles just fine but there seems to be a slight delay in throttle when you rev it up. it is not over heating but there is a bad rattle in the cadilitic converter but like i said it is not over heating and shutting off had it run in idle for several hours and not once shut down. IT seems that it wants to shut down with either the break or under a load. I need help!!! out of Ideas ,please anyone. all suggestions welcome.

What u should do first is check to see if the ecm has set any codes.If the tps is misadjusted or going bad a code 21 would set.As for the maf sensor a code 33 may set which u would need to check the voltage with a multimeter to make sure it is with in tolerance should b 0.5 volts at idle and 4.7 volts wide open throttle.Check this site for a step by step on checking the maf http://www.wellsmfg.corp.com click on diagnostics volume 2 issue 1 this will show a step by step to check it with a multimeter.If I think of something else I will post it.

I already checked the ecm by jumping the OBD1. It just kept popping a code 12 which in my understanding is all clear no codes. But I did not think to check the voltage thanks we'll see what happens.

The way you have described it is kind of confusing, but it could be your TCC solenoid. Does it only sputter and stall after the car is warmed up and you reach 45 to 55 mph? The TCC solenoid locks up the torque converter in overdrive to get better gas mileage, cars around that year are notorious of having the solenoid go bad. This causes the torque converter to stay locked so when you try to stop it's like trying to stop a manual transmission in gear.... it stalls. When you restart the car it unlocks the TCC solenoid and you're ok until it locks up again. Find the connector (drivers side of the engine bay on the front of the transmission) and unplug it and see what happens.





You can't outrun the radio.

Red bird he specifically stated the car is a manual transmission,while yes automatics do present the same issue,his car is not a automatic.Also even if the egr was cleaned it may be defective or sticking causing the car to choke under the above circumstances.IF the egr has a vac line going to it ,remove it and if the problem goes away the egr is bad,just replace it.I know u cleaned it ,but if the rubber diaphram inside is losing vacumm or the pintal does not move freely up and down the egr is probably shot.That is something else to consider.OK

Yes, thanks the car is manual. I replaced the TPS today and it made the throttle more irradict. I;ve played around with the throttle screw and nothing In fact turening the screw 1.5 times around did not even change the throttle. The EGR seemed fine after I cleaned it everything moved more freely. I did not notice anything wrong with the pin tail. But suspisiously after replacing the TPS with the engine running I got a code 23 high voltage from the TPS(bran new) and still code 12 engine off. Yet though NOW when the car is sitting still at idle pressing hard on the breaks makes it sputter and stall out.(did not do it before) pumping the break will make the idle irratic. AND there is still that damn noise coming from the cattalitic converter but I pressed against the tail pippes and there was plenty of pressure and it did not want to die.( held as long as I could too). MY Guess is that it is probably the MAP sensor or the catalitic converter but it does not run hot and the cat (used my hand) did not seem like it was getting over hot either. the next thing i am thinking off also is dropping the GAS tank and checking for sediment in it but it is at least 3/4 full.FUN,FUN,FUN. NOT!! I also took the vacume line off the break booster and closed it and tried the breaks again with it running and the same thing happened as before So Now I'm going to pull the throttle body again and the plenum and check once more for vacum leaks. If all else fails I will propably just replace the darn MAP sensor 40$ part that'll wait till after the fifthteenth though. military pay periods. it sucks. RON if you have anymore inputs it would be greatly appretiated.

My EGR does not have a vacume line it is all electrical so I'm wondering if it is the MAP sensor

Here's a thought. I had this problem with my Bonneville. Exact same problems. I had checked the fuel pressure and it was fine, but we traced the problem to the pressure regulator. The diaphram inside was bad and when I'd put the car under load the regulator wouldn't adjust properly. Sometimes it would and sometimes it'd die just like you're describing.

I'll be learning to read any day now





You can't outrun the radio.

Well it's clear that the car dies under a load or throttle.IF ur cat is not over 5yrs or older and the car has been kept up I might rule that out.While feeling pressure is good from the rear a clogged cat or partially clogged cat would cause the car to die and have irrattic idle bc its not breathing properly even tho u feel exhaust being some what normal.On the other hand if the fuel pressure regulator is leaking or not adjusting as posted above the car would create similar problems.U may need to take a look at that to see if the gasket is leaking any fuel bc it would b a possibilty mine had a leaking gasket and dumping fuel on my tbi and ruined my cat due to running too rich.Thats what comes to mind based on ur finds if I think of any thing else I will post it.If ur fuel pressure is 41-47 psi and then disconnect the vac line it should decrease 5-10 psi if it does not the fuel reg is the problem at least based on my book knowledge.

ok checked out the car again a little today. found moister in the EGR cleaned it again. but let me state this new trouble shooting. like I stated before I am reading a code 21 (car running) high voltage to TPS, TPS is new. Pumping the breaks or pushing them hard causes the car to idle irradically but once you rev it it will settle back to norm, if I don't it will sputter and die. Jumping the OBD1 somehow caused it to want to sputter and die today as well. It only did it a couple of times though. Still reading a code 12 with engine off. so tomarrow I am going to check the resistance to the MAP sensor. I am not sure how to tell if the pressure regulator is bad. I was told by AutoZone that if it were bad it would have a hard time starting then dieing but it does not and stays running not under a load. I'm starting to wonder if there could be a short somewhere picked up a multimeter today to trouble shoot that idea. Any thoughts on this one, it seems just when I think I fix the problem it does something else to through me and anyone helping off to left feild shruding their shoulders. anyone now how to take curses off of vehicles HEHEHEHEH. cause it sure feels like it has one and doesn't want to cooperate. thanks to everyone helping keep advice coming cause it keeps me focused and gives me more knowledge. I am use to FORD Mustangs. my all time favorite car. This one is my wifes I got it as a gift for her but Now I wonder......

Calvin Rife wrote:anyone now how to take curses off of vehicles HEHEHEHEH. cause it sure feels like it has one and doesn't want to cooperate.

Voo Doo priestess? Cut up a live chicken, do a little dance, speak a little gibberish, basically make a total ass out of yourself, take two aspirin and call me in the morning.

check your Air idle sensor. mine went bad on my 89 and it did the exact same thing. also. check the MAP sensor. on my other 89 it went and only stalled when i would be driving and come to a stop. but it was every time i stopped rapidly. if i slowed down for a long long distance it wouldnt do it. check both out. if u knwo someone with a 3.1 u could swap them out real fast to see if it corrects the problem rather than going out and buying each individual sensor. hope you can get it runnin.


PJ

i had the that same problem 0n my 90 3.1 i finally traced it to a bad coil and also if the gas tanl was not full the gas would slosh around in the tank and drop fuel pressure and die also. i have a couple coils lying around after i built a new 3.1 let me know if you need one. ill hook ya up Matt

I tested the map sensor and it was reading .6-.8 volts which is way below the specs for the map sensor. So next week I am going to replace it and hope that it fixes the problem.