pontiac 6000 engine problems

[fireman39]

can some one help me PLEASE. I have a 1988 pontiac 6000 2.8 fuel injected. I have problems some times with it lurching while driving. Some times i will accelerate and it will smooth out. but if i hold the accelerator while driving around 40 to 50 km/h it will feel like its cutting out. I changed the coil packs and plugs and wires. But no help. it seems like the times it is doing it the check engine light is not on, go figure. some people has told me it might be the fuel regulator some said everything from the map sensor to low fuel pressure. I have not tryed all of those as of yet. Can anyone give me some advise on what to look for first. i am up against the wall on this one

[maxwedge]

Welcome to AF. Have the fuel pressure checked under the conditions that it happens, replace the fuel filter if not done, also.

[2.8litre]

I have the same exact same car with the same problem but it seems that my throttle cable seems stiff. When I take off it seems like i gun it but i try to ease into it and other times it takes off smooth

[mrlightrail]

When you replaced the coil packs, did you replace the ignition module also? (the unit that the coil packs plug into). That unit may be faulty. These units have a nasty habit of failing, and are in a bad location as they are very susceptible to damage from water splash during wet weather.opcorn:

[dcjredline]

Well you say there is a check engine light what is that saying? My guess is TPS. Read the CEL code and that should be leading you to the right spot instead of guessing.

[royengle]

Originally Posted by My Sixth Gear
I encountered a similar problem with the 3100 where the cylinder six fuel injector was shorted and only had a 1 ohm resistance value, this caused all the current to go this injector and the other two injectors on the same bank weren't firing causing the engine to stall. Try checking the resistance values of the injectors, all should be around 6 or so ohms.

[Tech II]

Wow, people jumping in on posts, one, two, and 7 years after the fact....

Royengle.....just a few things.....this engine was multiport, which meant that, one driver in the ECM grounded three injectors(1/3/5) at once, another driver fired the other 3 injectors(2/4/6), at the same time.....

So if one injector shorted, it doesn't steal current from the other injectors(they are three parallel injectors each getting BAT volts).....what it means is, there is an increase in the total current flowing on the one wire back to the driver.....the driver has a way of sensing this, and when it does, it shuts down and all three injectors on that circuit lose their ground......

All the injectors are 12 ohms not 6 ohms...quick way to check this is, take a reading of all 3 injectors at once...since they are all in parallel, they will ohm out to 4 ohms in parallel......if less than this, than you know one or more, are shorted......if one is open, it will measure 6 ohms...two are open, it will measure 12 ohms....

Main culprit I found with this was, mice....they would like to build a nest under the upper plenum, and proceed to eat the insulation off the injector harnesses....