88 ranger 2.9 erratic idle, sudden rpm drops idle and load, sputtering just when cold, slowly acceleration and can’t go above 60 mph

[LittleDevinBro]

I have an 88 ranger xlt 2.9l dual tank. I have done many things to it I’ll list below. I have also tested lots of things I’ll list below.

The issues I have are as follows; it has erratic idle, sudden drops in rpms when idling and when accelerating. Happens more when under heavy load and acceleration. I also have an issue where if I just hop in the truck start it up and go drive when engine is cold it will sputter maybe 10 times until it warms up and then it stops sputtering. Usually it doesn’t sputter after it warms up unless I turn off the truck and then turn it back on. Then it only does it once or so. I also can’t get the truck to accelerate above 60. It seems like it has a lean or rich mixture or something like that when accelerating. It accelerates slowly as well

Replaced:
-distributor, including cap and rotor
-ignition coil
-spark plugs and wires
-fuel injectors
-high pressure fuel pump
-fuel filter
-upper and lower intake gaskets
-any other gaskets you can replace when doing intake gaskets
-map sensor, o2 sensor, coolant temp sensor, intake air temp sensor, oil sender

Tested:
-compression test was stock compression on all cylinders (190)
-vacuum test was good. I believe it needs somewhere between 20-24 hcg and it was 23
-iac valve I’ve replaced and it didn’t change anything so I put the old one back on
-throttle position I replaced and didn’t change anything so I put old one back on

I want to test my fuel pressure at the rail but none of the fittings I’ve tried will fit my ranger for some reason. I went to oriellys and their kit didn’t fit.

I do understand as well that any of the parts I’ve replaced could be bad out of the box so any comments or suggestions are welcome. I just want to get my truck running well and I can’t seem to get it to run. I’m chasing my tail it seems like

 

[Uncle Gump]

Fuel pressure test is mandatory...

The first step of any drivablity concern.

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[LittleDevinBro]

Yeah I need to do that. I appreciate your input and will get back with fuel pressure readings. My fuel gauge doesn’t work as well. I believe that’s early signs of my in tank pump going out

 

[SenorNoob]

What did plugs look like when you changed them? Might tell you if it's lean/rich. The Harbor Freight fuel pressure tester I have has the right fitting.

 

[LittleDevinBro]

I believe the last time I pulled them they indicated lean. And I might have to go see what my harbor freight has for testers

 

[Uncle Gump]

Did you keep your old injectors?

Replacement injectors are a buyer beware kinda thing these days. If you bought the cheapest on Amazon or ebay... I'd put the original injectors after clean and test was performed.

 

[LittleDevinBro]

Yeah I kept old injectors. I installed factory oem ones but I wasn’t 100% sure if they were going to perform correctly. I had heard the same thing and potentially just to get the injectors cleaned but it was the same price and figured why not go with new. If you are thinking I should get them cleaned and try it out I definitely could.

 

[Uncle Gump]

That's on you... glad to see you kept them.

 

[Uncle Gump]

I have a factory set i was going to send out and have done.

There are places that sell tested matched sets... spendy... yes. Worth it... probably.

 

[Terrys87]

Seen you have checked several things. I dont see your Fuel Pressure Regulator on the list. I have had that to fail. I have seen in the computer that some capcitors fail, you can open it up and see them right away. I would do a fuel pressure test like others have mentioned.

I have same truck as you, I had an erratic idle. Mine wound up being the aftermarket TPS, I installed a used factory Throttle Body Assembly and fixed mine. Also there is a fine setting on getting the TPS adjusted correctly. Another reason I went with a used assembly.