voltageyz0 Posted January 22, 2009 Share Posted January 22, 2009 hi ive got an 88 mj 4.0 5speed 2wd and when i start it up it stays at 2500 rpm and when i press the gas it bogs down then goes. then when i let off the gas it stays at what ever rpm i was at for about 2 or 3 seconds and goes down slowly. every once i a while my gas pedel feels hard to depress but when i try again it works fine. the motor has even shut off on me while driving. and this is a different subject but the last few times i have filled up on gas i have been getting 8 mpg and before i got 8mpg i was getting 11mpg. anyone know of ways to improve that? any help on both topics would help. thanks akot. kevin Link to comment Share on other sites More sharing options...
JeepcoMJ Posted January 22, 2009 Share Posted January 22, 2009 fixing your throttle issues will fix your gas mileage...you should be getting 15mpg at the very least. sounds to me like a sticky throttle cable, or sticky throttle position sensor, or gummed up throttle body. also, clean your injectors. Link to comment Share on other sites More sharing options...
voltageyz0 Posted January 22, 2009 Author Share Posted January 22, 2009 ya when i looked into the throttle body it was pretty dirty. soon I'm gona take it all apart and clean everything. with the injectors i will most likley buy new ones. thank you Link to comment Share on other sites More sharing options...
BLHTAZ Posted January 22, 2009 Share Posted January 22, 2009 with the injectors i will most likley buy new ones. thank youThat will make a huge difference :thumbsup: . I bought some for mine and saw a 14% increase in MPG. The best place to get them is through this guy as he offers a discount to members that I refer... Precision Auto Injectors. Put ' JEEP ' in the coupon / discount code when checking out for 10% off. Link to comment Share on other sites More sharing options...
Eagle Posted January 22, 2009 Share Posted January 22, 2009 Fast idle is often caused by a dirty IAC (Idle Air Controller). However, I also found that there can be a mechanical cause. The throttle cable comes through the firewall to a ball/socket linkage (a bellcrank) mounted below the brake master cylinder. From there, there's a rod that runs up to a second ball/socket linkage, which attaches to an arm off the throttle body. After a lot of time and miles, the balls get rusty and resist allowing the linkage to move. I popped mine off, sprayed the sockets with PB Blaster, and reassembled. A few days later, after the PB had cleaned things up a bit, I popped the rods off again and sprayed a little white lithium grease in the sockets. Link to comment Share on other sites More sharing options...
voltageyz0 Posted January 22, 2009 Author Share Posted January 22, 2009 thanks for your help and the discount code. and when i put the throttle body spacer in they were not rusty so it is probally rhe iac. thanks Link to comment Share on other sites More sharing options...
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