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So, I started this thread here: http://www.60degreev6.com/showthread...3.1+hesitation and never found a solution. After about a month of trying different fuel-tip in tunes, I've gotten nowhere. I wanted to start this thread to make a quick summary of everything, and see if anyone has some suggestions for this annoying problem.
My car is an 86 Fiero. It had a 4 cylinder that burned oil and a 5 speed tranny. My uncle had a 1990 Lumina, with a good 3.1, that i got for free. I swapped the engine into my Fiero, along with the Lumina ECM. After a few months of rough idling, the car started to sound like a Lumina (EGR valve was stuck I think). I had the ECM reflashed with a 90 Lumina 5 speed program.
Now that it ran good, I started to notice a hesitation problem.
The best way to describe the problem is like this. The car will be idling, and if I tap the gas very quick and light, the engine will bog down 100-200 rpms or so, then rev up. Sometimes I will give it about 1/4 throttle quickly, and hold my foot there. This sometimes will cause the car to bog down badly, almost killing it at times, before it revs up. When I am driving the car, the engine will buck slightly on each shift and is very annoying. It is extremely bad especially when I first shift into 2nd after a cold start. It almost kills the car sometimes. But anyway, it seemed to me like the car wasn't getting enough gas, so I sent the chip back to my programmer, as he said he would increase the fuel at tip in. When I got the chip back, it seemed to dissappear. Then of course, 10 minutes later it came back. All this seemed to do was make the car hesitate and rev quicker, and not eliminate the hesitation. I sent it back once again, and the tip in was increased more. The hesitation was still there, and the car would flat out fall on its face if you went full throttle. I figured it was giving it way too much gas, so sent the chip back to get reprogrammed to stock. I'm ruling out that this is a tuning issue.
Among the things I have tried so far: New plugs, new plug wires, different coils and ICM, three TPS sensors, at least 5 MAP sensors, two oxygen sensors, and two IAT sensors. The only thing I've noticed that is weird, is that the car acts no different with the 02 sensor unplugged. Honestly, I have no idea what the hell that could mean.
The only thing I can think of to try now is a different ECM. I've tried so many sensors, replaced ignition components, checked the fuel pressure (it was good), and god knows what else. I do have a scanner available to use, but I am getting so lost as to what to try next. The thing has been getting 30 MPG, which is great, but it can be annoying to drive. Ive been messing with this for close to a year, and it only seems like I'm taking steps back. Sorry for such a long winded post, but I would LOVE to fix this thing!
My car is an 86 Fiero. It had a 4 cylinder that burned oil and a 5 speed tranny. My uncle had a 1990 Lumina, with a good 3.1, that i got for free. I swapped the engine into my Fiero, along with the Lumina ECM. After a few months of rough idling, the car started to sound like a Lumina (EGR valve was stuck I think). I had the ECM reflashed with a 90 Lumina 5 speed program.
Now that it ran good, I started to notice a hesitation problem.
The best way to describe the problem is like this. The car will be idling, and if I tap the gas very quick and light, the engine will bog down 100-200 rpms or so, then rev up. Sometimes I will give it about 1/4 throttle quickly, and hold my foot there. This sometimes will cause the car to bog down badly, almost killing it at times, before it revs up. When I am driving the car, the engine will buck slightly on each shift and is very annoying. It is extremely bad especially when I first shift into 2nd after a cold start. It almost kills the car sometimes. But anyway, it seemed to me like the car wasn't getting enough gas, so I sent the chip back to my programmer, as he said he would increase the fuel at tip in. When I got the chip back, it seemed to dissappear. Then of course, 10 minutes later it came back. All this seemed to do was make the car hesitate and rev quicker, and not eliminate the hesitation. I sent it back once again, and the tip in was increased more. The hesitation was still there, and the car would flat out fall on its face if you went full throttle. I figured it was giving it way too much gas, so sent the chip back to get reprogrammed to stock. I'm ruling out that this is a tuning issue.
Among the things I have tried so far: New plugs, new plug wires, different coils and ICM, three TPS sensors, at least 5 MAP sensors, two oxygen sensors, and two IAT sensors. The only thing I've noticed that is weird, is that the car acts no different with the 02 sensor unplugged. Honestly, I have no idea what the hell that could mean.
The only thing I can think of to try now is a different ECM. I've tried so many sensors, replaced ignition components, checked the fuel pressure (it was good), and god knows what else. I do have a scanner available to use, but I am getting so lost as to what to try next. The thing has been getting 30 MPG, which is great, but it can be annoying to drive. Ive been messing with this for close to a year, and it only seems like I'm taking steps back. Sorry for such a long winded post, but I would LOVE to fix this thing!
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