jeepster90xj

so i have owned my jeep for the past year and a half now and ever since ive owned it the engine stutters right around 1500 rpm's. it doesnt do it in neutral or park only when it is in drive. also it does the same thing if i accelerate REALLY slow. its almost like the the engine loses spark for a sec and then comes back but it does it multiple times until i either let off the gas a little or put my foot in it a little more. Also, every now and then it runs a little rough when it idles. the IAC is new, the TPS is new and adjusted correctly, new cap and rotor, new plugs and wires, and a new o2 sensor. i have not been able to figure this out no matter what i try so any help is greatly appreciated. The jeep is a 1990 jeep cherokee with the 4.0. thanks in advance.

No4x4Yet

Jeep doesn't have a MAF right? But what bout what's measuring the air flow

freegdr

Have grounds been cleaned ever ?

mdnov

How many miles do you have on it?

jeepster90xj

No4x4Yet- What is an MAF?
freegdr- yes the grounds have been cleaned in the last 3 months
And there are 158,000 miles on the odometer, less then 6,000 miles on the engine because i replaced the motor with a remanufactured one when i got the jeep.

cruiser54

Sounds like your TPS might have a bad spot in it.

Do you have an analog meter?

cherokeeadam95

Buy a new wire connector for IAT and splice it in! So you have nice new lead connectors.

cruiser54

MAF is Mass Air Flow and you don't have one.

Have you ever checked the resistance in your sensor ground circuit?

No4x4Yet

Correct, the Cherokees measure the air flow volume differently, i just cant remember the name for it.

cruiser54

Their system doesn't use airflow at all. Mostly TPS for throttle position and MAP for gauging load from engine vacuum.

Parsnip

Does the temp make any difference in its tendency to stuutrr?

rrich

The name - Speed Density.

cherokeeadam95

seriously! this same this was happening to me, check all your wire connector plugs, NOT the sensors! what are your codes? just because there is current there does not mean you have a good connection.

jeepster90xj

Cruiser54-i dont have an analog meter just a digital one- should i get one?
also how do i check the resistance in the sensor ground?
Parsnip-no it does this whether the engine is warm or cold or running temp
Cherokeeadam95-how do you check codes on my year of jeep?
thanks for all the replies i really appreciate it

cruiser54

First off, there are no codes in a Renix Jeep. Cherokeeadam is mistaken.
Here's how to check the sensor ground circuit:

Cruiser’s Renix Sensor Ground Test
　
This sensor ground circuit affects the CTS, TPS, IAT, MAP, ECU and diagnostic connector grounds. It’s very important and not something to overlook in diagnosing your Renix Jeep as it is common for the harnesses to have poor crimps causing poor grounds. If any or all of the sensors do not have a good ground, the signal the ECU receives from these sensors is inaccurate.
Set your meter to measure Ohms. Be sure the key is in the OFF position. Using the positive (red) lead of your ohmmeter, probe the B terminal of the flat 3 wire connector of the TPS . The letters are embossed on the connector itself.
Touch the black lead of your meter to the negative battery post. Wiggle the wiring harness where it runs parallel to the valve cover and also near the MAP sensor mounted on the firewall. If you have an 87 or 88 with the C101 connector mounted on the firewall above the brake booster, wiggle it, too.
You want to see as close to 0 ohms of resistance as possible. And when wiggling the harnesses/connectors the resistance value should stay low. If there is a variance in the values when wiggling the wires, you have a poor crimp/connection in the wiring harness or a poor ground at the engine dipstick tube stud. On 87 and 88 models, you could have a poor connection at the C101 connector as well.
Revised 06/12/2012