Rough cold start

my 95 2.7 4cyl 4x4 had a misfire problem for a while where on a cold start she would misfire on cyl 3 for a minute and then level out and run good, so I had that fuel injector replaced. The problem did seem to go away for a little bit but just earlier today i fired her up and she was shaking all over and then eventually leveled out. Did I make a mistake by not just getting them all replaced? Or could it be a problem with the cylinder? Also when it would misfire before the engine light would come on but today the engine light never came on. Any suggestions?

 

Sounds like plugs or other ignition related to me. This year have the distributor? Or coil packs? If dizzy, then check the cap and rotor, make sure no corrosion, etc

 

My 95 2.7 with about 157,000 is a little rough and runs rich on cold start. Idles perfect once warmed up. Haven't put in the time to solve it yet, but it does have new plugs and wires, clean MAF, new IAC, and I have run quite a bit of injector cleaner through it. Also cleaned out the throttle body inlet (didn't remove it). All these were done just because I bought it with no history at about 154,000. All have made virtually no impact to that rick/slightly rough start.

 

Distributor but all of that has been changed recently and never fixed the issue.

 

If it was me, I would check the fuel trims first. If they are +- 5% you are pretty good. If not then you will have to get deeper into it with a leak down test to see just how mechanically sound the motor is. Is this the motor that has 300k on her?

 

Fuel trims? You're talking to a dummy lol so help me out. But yes she has just over 347k actually

 

I've also noticed if I stall the truck say trying to move it spots in the driveway, she will not fire back up for a little bit

 

I wouldnt be surprised if there isnt a crack in the head. the 4 cyls seem to have that issue in the higher mileage motors.

as to fuel trims. There are a few sensors in the exhaust that measure the oxygen content. depending on year/model/motor of truck there is either a A/F sensor (air fuel sensor) or an 02 (oxygen sensor) both do the same thing but different ways. As the motor is running the oxygen content is measured contstantly and the amount of fuel injected is adjusted. this happens almost instantly, within milliseconds. From a base ratio of apx 14 to 1, 14 parts air to 1 part fuel, if the sensor reads that to keep that ratio correct, more fuel needs to be added the fuel injectors stay open just a little longer and that gives a positive fuel trim and the opposite for the other way. If the fuel trims are greater than 5% either side of zero is an indication that something isnt right. Anything above or below apx 25% should light the CEL.

reading the trims for both short term, right now, and long term, over a period of time, you can be pointed in a particular diagnosis direction... are we talking a mechainical issue, the motor is burning too much oil or a manitenace issue/vacuum leak.

there is no magic bullet diagnosis here... someone with some knowlege is going to have to check it out. At that mileage you are probably going to need a complete motor as I wouldnt recommend just a head. Take a good look at the truck, frame, body, interior etc... is she worth it?

 

Ive already decided I'm keeping the truck for the long haul. she is rust free and has some dents but i love her. I'll have to suggest a couple things to my mechanic to look at.
Why do you say you wouldnt recommend just a head if it is indeed cracked?

 

not with that mileage on the bottom end. The total cost of replacing the head is going to be so close to replacing the motor that it isnt worth it. If you were doing it yourself *free labor* I would say go for it.
Replacing the head means replacing the chain which means taking the front of the motor apart... at that point you only have motor to bellhousing bolts from just taking the motor out.

 

Okay makes sense, so in your opinion should I just run her till she pukes out or should I be looking at throwing a new motor in?

 

new motor, depends. I have had good luck with used JDM motors.

I think yours is early enough that she has a distributor, if so

https://www.jdmenginesnewjersey.com...nner-1995-to-1996-3rz-fe-27l-distributor-type

 

Would it be ridiculous if I wanted to throw something a little bigger in?

 

unless it was complete, meaning wiring harness with PCM for the same equipped truck you will run into issues with wiring. It appears that Toyota makes specific harness for each motor/trans/drive type AND if it is 49 state or CA.

 

Is there a way to check the fuel trims w/o OBDII? If there is a way, I'd like to check mine also.

 

no... need a scanner.