Ok guys i just did a complete tune-up on my 93 cherokee. new plugs,wires,dist cap, rotor, fuel filter, cleaned the throttle body and tps. I also sea foamed it. I wont say its a rough idle but it like spits at my every couple seconds. Any ideas what it is.

 

vacuum leak? maybe?

 

May have a plug wire switched to wrong spark plug. Check them again to make sure there all in the right place.

 

Two questions...

What did you use the 'clean' the TPS???

What kind of plugs???

If you are using expensive plugs you are throwing your money away. The 4.0l is well-known to love the cheap plugs....

The TPS is a completely external sensor, there is really nothing to clean... But getting the wet or covered in some spray cleaner is not a good idea.

Now cleaning the IAC is a completely different thing. It needs to be pulled and cleaned every once in awhile.

 

i say check firing order first, and then check for a dropped spark plug with a smashed gap. i see that all to often, one gets dropped, or just not checked, and the gap is wrong. and make sure you are using champion plugs, nothing platinum and junk. many people have complained that platinum plugs actually made it run worse.

 

i think the guy at the parts store gave me platium tips. Ill double check. Also i did clean the ics with throttle body cleaner

 

Did you gap the plugs? If so @ what.. Sounds like one of them has too much gap and is misfiring.
Aviod the use of platimum plugs, I personally use NGK plugs or Champion.

 

pull all your plugs, one at a time and regap them to .035.
no plugs come pregapped, and yeah, just use the cheap NGK or Champion. don't buy into those platinum plugs, leave those for the high compression tuners.

check and double check the wires so they're in the correct firing order.

 

Double checked wires and also pulled plugs twice and gaped at .035 and still rugh idle. i mean it idle ok but it will spit at me like once every minute. idk whats up with it

 

still rough idle guys

 

how's your fuel pressure at the rail?

what's the tach doing? is it jumping around or steady rpm.
maybe the harmonic balancer? the rubber has been known to come apart.

i don't know...

 

i just remembered getting some of the cheaper line parts, and having similar problems. cheapo cap and rotors can do this sometimes, i had a bad wire on an xj to after a couple weeks, i could hear it arcing at the boot.

if this absolutely wasn't happening before the tune up, and is after, i'd take parts back. i'd check the plugs for spark leaking out the porcelin also.

 

Did your CEL come on when you sea foamed it? You may just need to disconnect the battery and reset your ECU.

 

nop no cel man. jpdocdave i bought the best parts available at the parts store but i cant figure it out. One thing i did notice with the plug wires is that i thought the one is suppose to be 8mm's and the other 6 are suppose to be 7mm's, mine are all 7mm

 

I've just put accel 8mm on mine with el cheapo Autolites as close to champion as i could get, and she purrs @ 204k miles. Also installed distro/rotor and dunno if it makes a difference but has brass plugs.

So if its not a plug/wire issue, id be leaing towards something that Seafoam could have got in contact with. I like Seafoam-Top Engine cleaner. Good stuff. Just might leave something behind yea know.

Anything wrong with the O2 sensor would prolly trip a CEL, ahh heck i dunno man...Good luck.


Travis