Decelerating to stop the engine almost stalls

Tiny
WESLEY BENNETT
  • MEMBER
  • 1987 JEEP WRANGLER
  • 89,000 MILES
1987 Jeep Wrangler YJ with 4.2L straight 6. When decelerating to stop the engine almost stalls then returns to normal idle. What could be causing this?

When decelerating to stop, engine almost stalls then returns to normal idle.
Saturday, April 28th, 2012 AT 4:56 PM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Could be a vacum leak, throttle body being dirty or a bad idle air control motor. Get it checked to confirm.

Roy
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Saturday, April 28th, 2012 AT 5:02 PM
Tiny
WESLEY BENNETT
  • MEMBER
  • 2 POSTS
Thanks Roy. Does the fact that the previous owner removed the catalytic convertor have any effect on it?
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Saturday, April 28th, 2012 AT 5:33 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Not really, it should have no effect on this condition.
Roy
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Saturday, April 28th, 2012 AT 5:35 PM
Tiny
CJ MEDEVAC
  • MECHANIC
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MR. 258 VERY WELL MAY HAVE A VACUUM LEAK AS ASEMaster6371 MENTIONED

HAS THE EMISSIONS RELATED VACUUM EQUIPMENT SORTA BEEN DISAPPEARING OVER THE YEARS?

I HAVE MESSED WITH MOSTLY CJs OVER THE YEARS, MY SEVEN, AND MANY OTHERS.....ALL SEVEN HAVE BEEN MY DAILY DRIVERS EVER SINCE THEY LET ME ON THE ROAD IN 1987.

RECENTLY I MADE A NEW JEEP BUDDY, EVEN THOUGH HE IS A YANKEE. HE WAS SORTA HESITANT AT 1ST, HE WANTED ME TO FIX HIS JEEP AND HE WAS GONNA PAY ME...I REFUSED AND TOLD HIM THAT I WOULD HELP HIM DO IT FOR FREE. THIS WAS HIS 1ST EXPERIENCE DIYing HIS OWN STUFF, HE'S 55 YEARS OLD, TOOK AN EARLY RETIREMENT....AND NOW HE STRUTS AROUND LIKE A BANTAM ROOSTER NOW HAVING REPAIRED HIS 1985 CJ 7 MOSTLY WITH MY INSTRUCTION AND USING MY TOOLS.

HECK, HE WAS SO PROUD, HE'S DONE GONE OUT AND PURCHASED HIS OWN TOOLS AND TEST/ TUNING EQUIPMENT

THE BIGGEST PROBLEMS WITH HIS WERE OPEN VACUUM LINES/ PORTS----3 LOOSE INTAKE TO HEAD BOLTS---A CARB THAT SOMEONE HAD "FORCED" THE MIXTURE SCREWS AND SORTA RUINED THEIR SEATS

WE'RE NOT EMISSIONS TESTED HERE, AND HIS CAT HAD BEEN REMOVED YEARS AGO. WITH THE LAST OF THE CJs, AND THE BEGINNING OF THE WRANGLER---THEY USED THE PRIMITIVE COMPUTER SYSTEM WHICH WITH ALL IT'S ELABORATE EXTRA EQUIPMENT....DID NOTHING MORE THAN ADJUST THE CARBURETOR USING THE STEEPER MOTOR THINGEE HANGING OUT OF THE BACK OF THE CARB WITH THE WIRES GOING IN

THE COOL THING IS--YOU CAN BACK UP IN CJ YEARS, GET RID OF THE EXPENSIVE, PROBABLY NOW SCREWED UP CARB ON IT NOW....AND ELIMINATE ALL OF THE EXTRA EQUIPMENT THAT IS NOT NECESSARY......BASICALLY MAKING YOUR RIG INTO A 1979 CJ UNDER THE HOOD

WE WENT DOWN AND ORDERED A 1979 CJ CARB TO TAKE THE PLACE OF HIS '85---ADVANTAGE IS NO WIRES IN THE BACK--IT HAD A WARRANTY--AND BEING REBUILT, WORN OUT PARTS HAVE BEEN REPLACED (NORMALLY IF YOU DO YOU OWN REBUILD, YOU ARE KINDA STUCK WITH "YOUR OLD WORN PARTS"

JUST DON'T TURN IN YOUR CORE UNTIL YOU JEEP IS UNDERWAY....SEEN PEOPLE LEAVE THEIR AIR CLEANER BRACKETS AND SUCH ON THEM, ONLY TO FIND THE CORE WAS SHIPPED BACK NEVER TO BE SEEN AGAIN, IF THEY JUST HAD TO HAVE THE CORE CHARGE BACK RIGHT THAT SECOND!

AFTER I MADE RICK DO MOST ALL OF HIS WORK

HE TUNED IT PERFECTLY

THEN I SHOWED HIM THAT HIS ENGINE WOULD IDLE SMOOTHLY AT 300 RPM----OF COURSE WE IDLED IT BACK UP TO THE CORRECT IDLE SPEED OF 680 RPM, AFTER "SHOWING OFF".... REMEMBER, BEFORE IT WAS IMPOSSIBLE TO IDLE BELOW 1050 RPM AND IT WAS NOT SMOOTH AT ALL.

IF YOU WOULD LIKE TO DIY YOUR PROBLEMS, AND ARE SORTA SKEPTICAL/ SKEERED, I AM WILLING TO STICK IT OUT WITH YOU, AS I ALWAYS TRY TO DO IN THE CJ 5 & 7 FORUMS

https://www.2carpros.com/questions/2007-ford-taurus-tune-up

UNDER TWO CONDITIONS

YOU REALLY LOVE YOUR JEEP

YOU REALLY TRY HARD TO MAKE HIM HAPPY

I WISH I HAD RICK'S TESTIMONIAL!

THE MEDIC
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Sunday, April 29th, 2012 AT 12:51 AM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
UP ABOVE THERE---TYPED IN WRONG INFO--I GOT MY LICENSE IN 1981 TO BE ON THE PUBLIC ROADS. DRIVEN CJs EVER SINCE.

THE MEDIC
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Sunday, April 29th, 2012 AT 3:09 AM

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