20 Most Recent 1991 Isuzu Pickup Questions & Answers

This is almost 30 years, any codes? First!!!

Did you pull the vacuum line off the regulator? When the regulator fails, you get more return flow and flow out the vacuum port into the engine.

this car EFI, or CARB, ill toss COIN, EFI gas.what 4 cylinder, name it there are 7 used.I'll now toss my coin land on GAS 4 cylinder engine. (in usa?)is it racing too fast hotor RPM too low hot.?we cant guess what your statement above means.butthe exhaust manifold cracks will cause the 02 oxy sensors to LIE,to go lean (0volts ) this cause the fuel injectionto go RICH, (cause and effect closed loop rules)and can idle too slow. (see that word SLOW)the wrong word you used, after reading this vast times. "NOT idle at very low rpms"i decode this to mean?NOt idle at proper low RPM (800 hot)or spec 800 rpm , is more clearthat means the idle races hot.this word is in all books on cars. engine RACESIF true RACES it's not :the exhaust crack, but can be if engine EFI slams in to limphome mode, do the flash codes show 12?you never did those did you , bad idea skipping that. Google isuzu diagnostic jumper and read.it's not he fuel tank ever,. not RACING.what can cause any map based engine to racewell frankly LOTS:but can be reduced to: (physics +)1: throttle cables jammed. no slack. bad.2: throttle valve jammed (gunk below it does that)(in the throttle body)3: all vacuum leaks, (put huge list here, ask)4: ISC or ICA valves stuck open5: engine not reaching and holding 180f will cause #4 above to fail, naturally. bad thermostat. cause.6: someone hacked your TB. (ask)TB = throttle body.vacuum leaks is an all day wall of text posti refuse. but do have links to them.

apply a hammer to the dash. hit it hard continuously until broken

old car, very old this is easy, to find, but can be many things, my tests cut this to 2 reasons. mostly. (leaks and isc failure tests) 1: ISC system is dead, (stuck idle speed contr. valve) 2: throttle cable stuck or set wrong, (must have slack) 3: vacuum leaks, on all cars with map sensors, vacuum leaks make the ISC loose control and RACES fast with full engine power. all MAP based EFI SYSTEMS, "speed density systems:

you must have some wiring problems which is touching negative and positive. start checking wires from the indicator lights and follow the wiring to the fuse box. might take some time to follow wiring. it might just be a globe connector too.

Bad O2 sensor, leaking injector, blocked air filter, and other possible causes. A restricted exhaust would also cause loss of power but not make the engine run rich.

Should b a data code some where on the bell housing also u can call the dealer service shop give them your vin number and they can look it up

Syncronizer

Did you actually change the fuel filter??? It sound like this is the problem. Did you also check the pick-up strainer on the pick-up tube on the fuel pump. this sometime also get plug up.

what seems to be the problem with the high beams

Caution *** For your safety, Installation of this electric fuel pump requires that it be wired through the oil pressure switch

put truck on jack stands disconect batt . remove driveshaft/ starter .torqconverter bolts if automatic. if standerd slave cyl .shifter linkage .when all ***** are out of your way remove crossmember under trans . if 6 cyl dont let distributor hit firewall remove bellhousing bolts trans should fall out ..... support trans with jack .....dont get under trans it is heavey!!!!!!!!!!!!!!