99 TJ 2.5L with some issues.

I finally put my TJ back on the road about 6 months ago. It had been sitting in my back yard for about 2+ years. There are a couple of problems i'd like to throw out to the group.

1.) it dosn't have much power (yea, i know it's a 2.5, but my 2.5 YJ had a lot more power) 2.) mileage sux (yea, i know it's a mailbox on wheels, but still) i get about 16 mpg on the highway. 3.) this ones trickyer. between 2000 and 2100 rpm if there's any load at all (maybe a slight hill) and I try to accelerate, it feels like i'm running out of gas, or like i'm missing 2 cylinders. lots of bucking and fighting. as soon as I hit 2100 rpm it's fine, like I hit a switch. the guy at the shop says I just need to downshift, and it's just bogging down, but i've driven standards all my life and i know what bogging down is, and this isn't that. 4.) after sitting a while, like a day, it starts kinda hard. i've been reading about the regulators and check valves and all that, and it's definetly a pressure problem. i'm planning on getting a pressure guage and checking all that out. 5.) CEL is on, computer shows an evap system failure. i've replaced the gas cap, and cleared the code. comes back on, same code, sometimes goes off on it's own, then eventually goes back on. seemes like mileage is much better when the light is off.

ok, those were more than a couple problems. it seems to me that everything, even maybe #3 , is fuel system related. and the jeep did sit for a couple of years. i'm planning on pulling the fuel tank and taking a look. anyone have any idea's of some specifics i can test (and how to test it) or any other wisdom?

-Zenophryk

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chrism
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So I just put my TJ back on the road 6 months ago. It had been sitting in my back driveway for 2+ years. there are a few things going on with it that i need opinions on. #1) it has no power (i know it's a 2.5l, but my YJ 2.5l had way more power) #2) mileage sux, getting about 16mpg highway (i know it has the aerodynamics of a mailbox on wheels, but still, should be 20-22) #3) CEL light is going on with a evap system failure code. i clear the code, but it comes back on, sometimes it goes off on it's own, then back on at some point. fuel economy seems better when it goes off on it's own, untill it comes back on. have replaced the gas cap already. #4) starts hard after it's been sitting for a while. i've read the posts about check valves and filters and regulators, and it's definetly acting like a loss of pressure, so now i have to figure out if it's in the regulator or check valve or injectors. #5) (this ones the biggest pain in my butt) between 2000 and 2100 rpm, if it's under any kind of load, like a slight hill, and i try to accelerate, the engine skips and bucks. feels like i'm running out of gas or skipping 2 cylinders. as soon as it hits 2100 rpm, everything's fine, if it's under 2000 rpm, everything's fine. it's like a switch.

i havn't checked fuel pressures yet, i'm planning to get a guage today and do some of those tests. but wanted to get some oppinions first.

Reply to
Zenophryk

So I just put my TJ back on the road 6 months ago. It had been sitting in my back driveway for 2+ years. there are a few things going on with it that i need opinions on. #1) it has no power (i know it's a 2.5l, but my YJ 2.5l had way more power) #2) mileage sux, getting about 16mpg highway (i know it has the aerodynamics of a mailbox on wheels, but still, should be 20-22) #3) CEL light is going on with a evap system failure code. i clear the code, but it comes back on, sometimes it goes off on it's own, then back on at some point. fuel economy seems better when it goes off on it's own, untill it comes back on. have replaced the gas cap already. #4) starts hard after it's been sitting for a while. i've read the posts about check valves and filters and regulators, and it's definetly acting like a loss of pressure, so now i have to figure out if it's in the regulator or check valve or injectors. #5) (this ones the biggest pain in my butt) between 2000 and 2100 rpm, if it's under any kind of load, like a slight hill, and i try to accelerate, the engine skips and bucks. feels like i'm running out of gas or skipping 2 cylinders. as soon as it hits 2100 rpm, everything's fine, if it's under 2000 rpm, everything's fine. it's like a switch.

i havn't checked fuel pressures yet, i'm planning to get a guage today and do some of those tests. but wanted to get some oppinions first.

Reply to
Zenophryk

The first post even worked, LOL!

I would be unplugging and checking out the TPS with a multimeter set on ohms to see if it has a dead spot in the throttle response and be cleaning the connection while unplugged. A bad connection on the TPS can cause strange things to happen.

I suppose it could be checked for voltage when live, but I don't know the method for that engine.

Isn't there a TSB for a pinch or crack on the vent near the tank causing a leak in the evap system on some?

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: N> So I just put my TJ back on the road 6 months ago. It had been
Reply to
Mike Romain

I run my wifes Cherokee on at least 89 octane all the time and it is noticablly smoother and has a bit more pep.

This sounds a bit low but them also if it is lifted and has big agressive tires MPG will suffer especailly if stock gearing is retained. My wife 2000 Cherokee with same engine and 5 speed does in high reens to around 20 in a urban driving with A/C in warmer weather but it is bone stock too.

This seems to be a quirk with the engine and emissions controls as there is a RPM rpm that it feels funny at times but is fine above or below it. My wifes has done this more or less since it was new.

Might check fuel filter and fuel pressure and maybe CPS (Crank Position Sensor) as when they get weak they can cause hard starting at times and eventaully complete failure.

Cannot help you here at the moment.

----------------- TheSnoMan.com

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SnoMan

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philthy

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