misfire under load
05-08-2003, 11:32 PM
#21
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Originally Posted by UserBrett
Originally Posted by fuddyduddy121
If the same problem seems to happen at the same throttle angle every time, it'* possible you may have a dead spot in the throttle position sensor, and it may need to be checked. The easiest way to do it is with a Tech 1. Move the throttle sensor slowly from idle to wide open and see if there are any jumps, or if the resistance increases in a uniform fashion. You can also do it with a multimeter too.
Is it also possible you could have a bad fuel injector?
Just an idea if you've tried everything else.
Is it also possible you could have a bad fuel injector?
Just an idea if you've tried everything else.
Originally Posted by UserBrett
Car starts fine, Idle is fine,Runs good until load and boost and low rpms
but can get the problem in 3 going up a hill but a lot harder to do.
Injectors rebuilt and tested,
new coils,icm(used),maf,map,fuel filter,nose cone,sparks plugs(2 sets),wires,
orderedO2(comming soon, Delco. I dont think this will help).
No back pressure problem.
?
but can get the problem in 3 going up a hill but a lot harder to do.
Injectors rebuilt and tested,
new coils,icm(used),maf,map,fuel filter,nose cone,sparks plugs(2 sets),wires,
orderedO2(comming soon, Delco. I dont think this will help).
No back pressure problem.
?
so I got a new one. No change.
The throttle is fine. Smooth change in voltage Wide open reads 4.08 v
Should this be closer to 5v?
Could be the injector but had them tested.
05-08-2003, 11:52 PM
#22
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Originally Posted by fuddyduddy121
Originally Posted by UserBrett
Originally Posted by fuddyduddy121
If the same problem seems to happen at the same throttle angle every time, it'* possible you may have a dead spot in the throttle position sensor, and it may need to be checked. The easiest way to do it is with a Tech 1. Move the throttle sensor slowly from idle to wide open and see if there are any jumps, or if the resistance increases in a uniform fashion. You can also do it with a multimeter too.
Is it also possible you could have a bad fuel injector?
Just an idea if you've tried everything else.
Is it also possible you could have a bad fuel injector?
Just an idea if you've tried everything else.
Originally Posted by UserBrett
Car starts fine, Idle is fine,Runs good until load and boost and low rpms
but can get the problem in 3 going up a hill but a lot harder to do.
Injectors rebuilt and tested,
new coils,icm(used),maf,map,fuel filter,nose cone,sparks plugs(2 sets),wires,
orderedO2(comming soon, Delco. I dont think this will help).
No back pressure problem.
?
but can get the problem in 3 going up a hill but a lot harder to do.
Injectors rebuilt and tested,
new coils,icm(used),maf,map,fuel filter,nose cone,sparks plugs(2 sets),wires,
orderedO2(comming soon, Delco. I dont think this will help).
No back pressure problem.
?
so I got a new one. No change.
The throttle is fine. Smooth change in voltage Wide open reads 4.08 v
Should this be closer to 5v?
Could be the injector but had them tested.
74 Pressure seatting 74 @(could be a c)40F
Injector # 0280150934 Bosch
05-09-2003, 11:54 AM
#24
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I dont know about Bosch, but every mechanic i have had said to use AC Delco parts.
I do know that even after removing the Bosch plugs, the new plugs didnt make any difference.
After reading tons of messages about this, I get the feeling that the ignition/fuel fault finding is a rogue symtom and we are trying to fix the wrong thing.
The TCC solenoid in the Trans that locks it into overdrive sounds a good fit. If it is slipping, that could cause my lower economy on the highway, the slipping could make it feel like the engine is missing. And it sort of did start to happen around the same time my trans started making a sort of squeeking/chirping noise when slipping into OD/ or under acceleration in OD.
Any thoughts on this ?
I do know that even after removing the Bosch plugs, the new plugs didnt make any difference.
After reading tons of messages about this, I get the feeling that the ignition/fuel fault finding is a rogue symtom and we are trying to fix the wrong thing.
The TCC solenoid in the Trans that locks it into overdrive sounds a good fit. If it is slipping, that could cause my lower economy on the highway, the slipping could make it feel like the engine is missing. And it sort of did start to happen around the same time my trans started making a sort of squeeking/chirping noise when slipping into OD/ or under acceleration in OD.
Any thoughts on this ?
05-12-2003, 09:45 PM
#25
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I have fixed it! 
As you may last recall I had just reinstalled the fuel injectors after having pulled them to inspect them. The car ran worse when I started it. I double checked my work and all was good. So I used a favor and borrowed a scan tool (no, I wans't ignoring you fuddyduddy121). It told me that #5 was a weak cylinder. I pulled the plugs again and 5 out of the 6 looked the same as before. But #5 was completely fouled up. I had done a spark test so I knew the spark was good. So even though the injector ohmed good I replaced it anyway. Now it runs great!
As you may last recall I had just reinstalled the fuel injectors after having pulled them to inspect them. The car ran worse when I started it. I double checked my work and all was good. So I used a favor and borrowed a scan tool (no, I wans't ignoring you fuddyduddy121). It told me that #5 was a weak cylinder. I pulled the plugs again and 5 out of the 6 looked the same as before. But #5 was completely fouled up. I had done a spark test so I knew the spark was good. So even though the injector ohmed good I replaced it anyway. Now it runs great!
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