Somebody help please


#1

i have a 1991 grand am 2.5 4 cylinder fuel injection. it has 186,000 miles. i know get a new car. hah! about six months back it started to cut out and back fire when i give it gas and attempt to get in to traffic. if i give it the gas slowly then it will not do this. when this probelm began i put new plugs in. recently, i changed out a vacume hose,the fuel filter, air filter and the filter to the crank. i check my fluids reguarly, and change the oil regularly. while in park i can reave the engine with no problems. somebody please help.

thank you


#2

You may have a fuel supply problem.

Perhaps the fuel pump is about to give up or the fuel pressure regulator is faulty or even plugged injectors.

Have the fuel system rechecked.

Does the engine sputter to a stop when you hit the gas hard or does the engine die as though you turned the key off?

Usually, when it sputters to a stop it’s a fuel problem and when it dies suddenly it’s a spark (ignition) fault.


#3

If the check engine light (or, engine symbol) comes on, you need to have it read. The trouble code could help in diagnosing the problem. The check engine code can be read by putting a jumper wire in the test plug under the edge of the dash, near the steering column. The test plug may have a cover on it. Pull the cover off. In the two holes in the upper right hand corner, put your jumper wire. Turn on the ignition switch. The check engine light will flash. It should always flash once, pause, flash twice. This is DTC code 12, which means the computer is working. Next, any othertrouble codes will flash. For example: two flashes followed by one flash would be the code for a problem in the throttle position indicator (sensor). So, too, would a code 22.


#4

The best way to troubleshoot this problem is with GM’s Tech 1 scan tool …which you don’t have, and I don’t have. Some tests, such as IAC “counting”, can’t be done without one. The work-around is to replace the iac (idle air control) valve. Also, replace the tps (throttle position sensor). Both parts have moving parts, get a lot of use, and will wear out. Both parts can cause your problem. It MAY be something else; but, these parts are CHEAP (relative to a “computerized diagnostic”: $150+). A replacement (re-manufactured) computer (ECM) is only about $100). +++First, put a fuel pressure gage on it ($42 from Sears) and observe the pressure while the engine is running at idle, in drive, at 2,000+ rpm. IF the fuel pressure holds at about 37 psi, go to the internet for the parts (best prices). Go to www.autozone.com, or, www.partsamerica.com for the tps $20, and the iac $40.


#5

It sounds like a dirty fuel injector. If I remember correctly, this car has the throttle body injector system, which is a single fuel injector over the throttle body. I’ll bet the injector is dirty, and not delivering the proper fuel when the gas pedal is stomped on.


#6

The work-around is to replace the iac (idle air control) valve. Also, replace the tps (throttle position sensor). Both parts have moving parts, get a lot of use, and will wear out. Both parts can cause your problem. It MAY be something else; but, these parts are CHEAP (relative to a “computerized diagnostic”: $150+).

This is your suggested work-around for not having the correct diagnostic tools??? Shotgunning parts can get expensive fast when the problem isn’t fixed. What do you do when you’ve replaced all those parts and the problem persists? The diagnostic fee starts to look very attractive then.