Very rough idle, stalls at idle - out of ideas

Reply Subscribe

Thread Tools

Search this Thread

Apr 2, 2023 | 06:05 AM

melimelo

Thread Starter

Newbie

Joined: Apr 2023

Posts: 1

Likes: 0

Very rough idle, stalls at idle - out of ideas

Hello everyone,

Long time reader here but this is my first post. Usually don't like to bother people for help.

So, I got a pretty good deal on a 4.0 94 zj, euro version. But it had so many problems that it ended up not being a good deal after all, everything is good now except one big thing.
There is sometimes a strong smell of gas in the cabin, with a very rough idle under load and often enough to stall the engine. In neutral I can feel that it misses sometimes but the needle stays bang on the 700rpm
The smell is intermittent but the rough idle is constant.

Living in a country with limited spare parts and having limited tools with me I had to change multiple parts at once, the only place I can find parts is rock auto with a two weeks delivery and delivery fees sometimes more then the parts themselves.

What I’ve changed so far:

Fuel pump (with a Bosh, seems to hold the pressure as there’s no priming anymore before I start)
Fuel filter (Wix)
Injectors (4 holes from k suspension)
IAC (standard, but I have the original mopar and makes no difference)
TPS (mopar)
O2 sensor because it was melted (first got a bosh then read that they’re not recommended so got an NTK)
Air intake temp sensor
Spark plugs (NGK, pre gapped as I didn’t have a gauge)
Spark plug coil (NGK)
Spark plug wires, delco and distributor cap
Air filter
Oil pressure sending unit
Thermostat to put a 195 because it runs really cool but it still runs as cool (1/4 gage)
PCV hoses because they were made out of tape and zip ties
And lastly I’ve changed the two sensors in the gearbox and the 3/4 spring because It was shifting bad.

Also, when I bought it it was missing the evap canister. It didn’t pass the emission test so I thought I’d put one back on.
Found

this one

on Amazon (doorman equivalent but can't find it anymore) but not sure it’s plugged in correctly as it’s not the original and different size. I’ve put the gas tank hose on the biggest input, the air box in the middle and the intake manifold on the smallest.

The cat is also noisy when the engine stops but I don’t think it’s the cause, I’ve drove it without the O2 sensor to test this and it has exactly the same symptoms. I think the map sensor is ok because I once left it unhooked by mistake and it ran like total crap.
Oil pressure on the instrument cluster is really high (more then half the gage at idle and 3/4 full throttle, it sometimes jumps when it’s having the rough idle issue)

I also have a spare CPS but couldn’t try it on because of a stupid metal bracket that’s bend over the bolt head.
edit: also replaced all the ground and power cables with heavy duty custom lorry ones.

There you have it, I’m out of money and out of ideas. Feel free to shame me for using the part cannon on this one.
What’s next ?

Last edited by melimelo; Apr 2, 2023 at 06:07 AM. Reason: added info about the ground cables