car spitting and sputtering BADLY. need help please

[blown02GT]

once again, the car is messed up. drove it home one night. ran GREAT. started it the next morning and now it's doing this. when you start it, you can hear a miss at idle, but when taking it down the road, it hesitates, spits, sputters, backfires, about anything you can think of besides a rod knocking, i've been working on cars quite a while and have never seen anything like this. i thought maybe IAC when i heard the irratic idle, but not this. the link in my sig has all the mods listed.. it also has a autologic chip (which i think may be the cause) any other suggestions?

Thanks,
Scott

 

[blown02GT]

well i tried everything else i can think of including a compression test. everything tests ok. guess i'll just send the chip back monday and see if that works

 

[2K1GtfromSC]

I left my MAF unpluged after installing my SC and it did the same things you said. You might check that and reset the computer.

 

[blown02GT]

hmmmm yeah i didn't check the MAF.. it may have come loose.. i reset the computer though and same thing. i'll check that out and see what happens.. thanks for the suggestion

 

[2K1GtfromSC]

hmmmm yeah i didn't check the MAF.. it may have come loose.. i reset the computer though and same thing. i'll check that out and see what happens.. thanks for the suggestion

Keep us posted.

 

[blown02GT]

well went out and cleaned the MAF. reset the computer and still nothing.. it's almost like 2 spark plugs and 2 02 sensors went out at the same time, which i really can't see happening.. is there any way to test a chip to see if it's bad? i heard about 1 in 6 of these things is bad from the distributor

 

[SPICOLI]

My cobra is doing the same thing, it starts great, but under any load it spits, sputters and runs like crap...I have been looking at a fuel problem, changed the filter to no avail, looking at getting a BBK fuel pump and checking the IAC Valve as soon as I figure out what it is?? Mine ran great, went to the store, came out and it started running bad....Mine idels fine though..Any words on BBK pumps?? Autozone wanted $214 for a pump...checked with R&E racing here in Cali and they have a BBK for $139....

 

[DaNd4Speed]

You might want to test out your coil packs. I messed up 2 of mine when I decided to clean my engine out and moisture got to them. The car behaved just how you described.

 

[sasscuba]

Happened to me and I pulled all the wires and looked into the boots to find one burnt. Under load did the same thing. Running on 7 is not the same as 8.

 

[yellow5.0cobra]

Try checking the IAC sensor.

I had the same exact problem, took me a while to figure it out.

 

[jbrown]

I am having the same problem with my 99 gt. It stumbles when under acceleration between 1k and 2k rpm. I changed out all the spark plugs. They were a little too red but it did not fix the problem, although it helped a little. The next thing I am gonna check are the coils that go on the plugs and the fuel filter. A friend with a 98 cobra suggested it was a 02 sensor but I would have thought my check engine light would have came on. Any suggestions????