bigums2

i have a 93 jeep grand cherokee laredo 4.0 stright 6. runs fine even when hot but when i turn it off and start it after 5 or 10 min it runs ruogh. ill start to drive and its bogging then after a bit itll run smoth agian. it also acts up when ive stoped for a bit like in a drivethrough or a long stop light

Bustedback

When was the last tune up?

bigums2

i just did a full full tune up this last week

Bustedback

Check engine light on?

PatriotGT

sticking injector, flooding the engine after a drive? Gas smell in the oil? Just a guess.

bigums2

no engine lights and oils good. someone at work told me there might be a bubble in the motor and to take it to a radiator specialist to have them push it out but not sure if he was just messing with me or not, im still gonna call around.

shouldofboughtanexplorer

no they were not messing with u they can vapor lock you can go to your local auto parts store and get a radiator flush kit it goes in your line and you hook the garden hose up to it insted of loosining your drain plug take off the cap and let her rip... lol thats like five dollars compaired to a hundred or so

Bustedback

Check the vacuum line at the fuel pressure regulator to see if you have vacuum, it could be a bad regulator.

bigums2

no bubble and good vacume. still checking anything that i can befor i give up and sent to a shop. to day im gonna change the fuel filter, valve cover gasket, oil sending unit; because its leaking. also gonna check my o2 sensor. hopefully that helps somthing.

Bustedback

You didn't happen to notice any raw fuel in the vacuum line that goes to the fuel pressure regulator or the nipple on the FPR, did you? I have seen one regulator that had a ruptured diaphragm and raw fuel was being sucked right into the intake manifold and causing the problem you described.

bigums2

just checked it and its dry as a bone. i stll havent checked the o2 yet. could it be that or maybe a leaking / sticking injector? any other ideas im lost.

Evil Bender

Mine acted like that when I bought it. I changed to NGK sparkplugs and it stopped.

Bustedback

In my 25 years of turning wrenches for a living, I have never seen a leaking injector in a gasoline engine. I'm not saying it can't happen, but it's very rare. Your o2 sensor may be lazy.

bigums2

well i reset the computer and havent had a problme so i think thats all it needed but ill find out in time thanks for all your guys help