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1987-2016 Wrangler Jammock Black 2.0 Jeep Hammock (YJ, TJ Rancho rockGEAR promotion gear from January 1-February 29,Zone Offroad Body and Suspension Lift Kits, Brackets, Disc

Unread 01-18-2006, 06:44 PM   #1
Registered User
1987 YJ Wrangler 
Join Date: Mar 2004
Location: Upstate NY
Posts: 2,388
Strange Engine Problem

In the middle of my 2.5 hour interstate highway drive (about 70mph) my engine starts running weird. All of a sudden it's hard to hold a steady speed because the engine wants to caugh and sputter... BUT if I push the pedal to the floor, the enine would accelerate seemingly with MORE power than normal. I was accelerating up hills with my 4.2L in 5th gear like I never have before, but as soon as I back off the gas it felt like I was hitting the brakes.

When I get off the highway I stop at the end of the ramp and the engine is idling at 2000 RPMs. Won't tap down or anything. I start moving again and it still feels like there's no power unless I'm flooring it. After shifting up to 3rd I stop at another stop sign... this time as soon as the clutch goes in the engine dies completely. Eventually it starts again but it's idling low and rough at like 400 RPMs.

Again I accelerate to third and it dies immediatly at the next stop. After restarting it's again idling low and rough. I rev. the engine a bunch of times and afterwards it's idling normally - smooth 700RPMs or so.

After this it's driving normally on a 45mph road with stoplights every 5-10 minutes. At some stops though it idles normally, others low and rough again.

'87 YJ Laredo - 4.0L, AX-15, NP231, 4.10s: 3.5" BDS, 31" Muds

'95 XJ - Donated drive train to the YJ, Parted out the rest

'51 CJ-3A - Buick 225 V6: Painless Wiring Harness, Warn Overdrive & Hubs, 2" Lift, 31" Muds
Tshark299 is offline   Reply With Quote Quick reply to this message
Unread 01-25-2006, 11:35 PM   #2
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1997 TJ Wrangler 
Join Date: Nov 2005
Posts: 51
if you have carb.. sounds like the diaphram blew... also their is a vacume line that goes to a metal vacume cone connects to it from the carb base.. that could have blew...could have been bad gasket between carb and manifold..or warped carb base... if you hve injection..then i dont have a clue...
stonehogg is offline   Reply With Quote Quick reply to this message

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