Coughing, Stumbling and Popping under load
04-27-07, 03:14 PM
#1
Coughing, Stumbling and Popping under load
I'm running out of things to check!
CAR: 86 N/A. No Cats or emissions equipment. Well maintained, rebuilt engine 25,000 miles ago, great compression.
My car has been running poorly for a while. Over rich and boggy. Now, as a matter of problem solving I checked the timing and it was way out. So, I put it all back to where it should be based on the stock timing marks, and now it is even worse! The car idles fine, but when you start to drive it and put some load on the car it coughs, sputters, stumbles and pops. So, I have done the following:
MAF: Checked resistance as per FSM and it checks out OK.
CAS: Checked resistance as per FSM and it checks out OK.
INJECTORS: Cleaned and flow tested. They are great.
PLUGS: New and properly gapped.
THERMO SENSOR: Checked resistance as per FSM and it checks out OK.
O2 SENSOR: Replaced when engine was redone.
What could be causing this condition? I've looked for vacuum leaks but haven't found anything obvious - could that be a cause? I originally thought it was a timing issue when I made this thread: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/ignition-timing-woes-643620/ but now I'm not so sure. My next step is to go out and build a code reader to see if it is throwing codes, but what else can I check now?
Thanks guys....
CAR: 86 N/A. No Cats or emissions equipment. Well maintained, rebuilt engine 25,000 miles ago, great compression.
My car has been running poorly for a while. Over rich and boggy. Now, as a matter of problem solving I checked the timing and it was way out. So, I put it all back to where it should be based on the stock timing marks, and now it is even worse! The car idles fine, but when you start to drive it and put some load on the car it coughs, sputters, stumbles and pops. So, I have done the following:
MAF: Checked resistance as per FSM and it checks out OK.
CAS: Checked resistance as per FSM and it checks out OK.
INJECTORS: Cleaned and flow tested. They are great.
PLUGS: New and properly gapped.
THERMO SENSOR: Checked resistance as per FSM and it checks out OK.
O2 SENSOR: Replaced when engine was redone.
What could be causing this condition? I've looked for vacuum leaks but haven't found anything obvious - could that be a cause? I originally thought it was a timing issue when I made this thread: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/ignition-timing-woes-643620/ but now I'm not so sure. My next step is to go out and build a code reader to see if it is throwing codes, but what else can I check now?
Thanks guys....
04-28-07, 05:05 PM
#5
Originally Posted by NCross
a bad or poorly adjusted TPS certainly wont help. when i push the TPS plunger all the way in while my car is idling it takes a huge dip in RPM and sounds funky.
I also used the LED tool to pull errors from the CPU, and sure enough there were none.....
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