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1g strange misfire on cold start

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brownfinger

10+ Year Contributor
1,957
11
Aug 26, 2008
Normal, Illinois
Hey guys. I pretty much joined because I can not figure this out. It's driving me nuts. 93 Eclipse, 2.0, NT Bone stock.
On cold start it starts OK, sort of. It used to fire right up and shoot to high idle. It would do this with vigor and verve, very healthy sounding. All you had to do was flick the key for a millisecond. It was that way from 1993 until about february2007.
Nowadays, it starts right up, but it sort of coughs and then slowly rises to high idle, but seems to be running smoothly. Untill...you try to move the thing. As I release the clutch and give it throttle, it stutters and bucks like a car with bad plug wires on a rainy day. Except that the plug wires are good, and so are the old ones that I just replaced with brand new wires. But it was pretty obvious that the wires weren't the problem, since the car runs like a swiss watch once it's hit normal operating temp.
I'll save everyone the trouble of suggesting the usual suspects:
(all parts genuine mitsubishi, brand new)
Throttle body, with TPS,ISC, FIAV, Entire assy.(It's been worn and sloppy for years)
O2 sensor
Coolant temp. sensor
Thermo Vacuum valve (I broke the old one removing the vac hose to test it)
Fuel and air filters
Front exhuast pipe ( the old flex was TOAST)
PCV valve
Plugs and wires
I'm getting tired of buying new parts to replace ones that weren't bad. The EGR holds vac, operates properly. I even removed it, cleaned it replaced the gasket. Upon inspection the plugs look pretty normal, no fouling, no wear, good gap. I swapped coils with a junk-yard part. Which is a bi*** to R&R. No difference. I checked the timing and it looked 2-3 degrees over advanced, so I retarded it to 5. This helped my milage on the highway, but not my cold misfiring, so I put it back where it had been. I performed the BISS setting procedure correctly.
Nothing seems to make a difference. I did all kinds of google and yahoo searches with every possible combination of terms and found a few other people have had the same exact problem, but no good solutions were offered. I haven't checked the TPS settings since I installed the new throttle body, But I've been assuming that $700 dollars to fix a sloppy throttle shaft is because the TPS is pre-adjusted so Satan's minions at the service department don't have to mess it up, anyway all previous used throttle bodies saw endless TPS adjustments in vein efforts to solve this problem.
I know I'm gonna feel like an idiot when I finally figure this out, but I'd like to get that over with sooner than later. So far the only thing I've heard that I haven't tried would be soldering new wires/terminals on the CTS connector, as the insulation is cracked.
Anyway, I'm waiting to hear from anyone before I try that. I'm loosing hair over this, trying all kinds of stuff and the problem only gets slowly worse.
Any Takers?
PS: No CELs. Computer shat and was rebuilt by Satan about 3 or 4 years ago
 
Hey guys. I pretty much joined because I can not figure this out. It's driving me nuts. 93 Eclipse, 2.0, NT Bone stock.
On cold start it starts OK, sort of. It used to fire right up and shoot to high idle. It would do this with vigor and verve, very healthy sounding. All you had to do was flick the key for a millisecond. It was that way from 1993 until about february2007.
Nowadays, it starts right up, but it sort of coughs and then slowly rises to high idle, but seems to be running smoothly. Untill...you try to move the thing. As I release the clutch and give it throttle, it stutters and bucks like a car with bad plug wires on a rainy day. Except that the plug wires are good, and so are the old ones that I just replaced with brand new wires. But it was pretty obvious that the wires weren't the problem, since the car runs like a swiss watch once it's hit normal operating temp.
I'll save everyone the trouble of suggesting the usual suspects:
(all parts genuine mitsubishi, brand new)
Throttle body, with TPS,ISC, FIAV, Entire assy.(It's been worn and sloppy for years)
O2 sensor
Coolant temp. sensor
Thermo Vacuum valve (I broke the old one removing the vac hose to test it)
Fuel and air filters
Front exhuast pipe ( the old flex was TOAST)
PCV valve
Plugs and wires
I'm getting tired of buying new parts to replace ones that weren't bad. The EGR holds vac, operates properly. I even removed it, cleaned it replaced the gasket. Upon inspection the plugs look pretty normal, no fouling, no wear, good gap. I swapped coils with a junk-yard part. Which is a bi*** to R&R. No difference. I checked the timing and it looked 2-3 degrees over advanced, so I retarded it to 5. This helped my milage on the highway, but not my cold misfiring, so I put it back where it had been. I performed the BISS setting procedure correctly.
Nothing seems to make a difference. I did all kinds of google and yahoo searches with every possible combination of terms and found a few other people have had the same exact problem, but no good solutions were offered. I haven't checked the TPS settings since I installed the new throttle body, But I've been assuming that $700 dollars to fix a sloppy throttle shaft is because the TPS is pre-adjusted so Satan's minions at the service department don't have to mess it up, anyway all previous used throttle bodies saw endless TPS adjustments in vein efforts to solve this problem.
I know I'm gonna feel like an idiot when I finally figure this out, but I'd like to get that over with sooner than later. So far the only thing I've heard that I haven't tried would be soldering new wires/terminals on the CTS connector, as the insulation is cracked.
Anyway, I'm waiting to hear from anyone before I try that. I'm loosing hair over this, trying all kinds of stuff and the problem only gets slowly worse.
Any Takers?
PS: No CELs. Computer shat and was rebuilt by Satan about 3 or 4 years ago

It seems that your problem is engine temp related right?, If you had any kinda decent scanner I'd tell you to see what your ECT temp/IAT temps are reading..
 
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