2002 ranger misfire rough idle
John C

Dolton, IL

#21 Nov 28, 2008
adam wrote:
help i have a p1537 code for ford ranger 2002, 2.3 5speed. truck runs like a champ but that damn engine light is on. military guy who needs to pass this inspection in nc. what should i do so i wont get ripped off. help please...
Had the same prob. Saw a u tube post on that code, which is manifold rail prob. Look for 1/4" broken hose on engine manifold down low on driver;s side of engine. There is a vacuum hose leading to a "solenoid" which has a second port facing down. The hose will be broken there. Fix that, disconect battery to clear code, then drive truck a few days to restore all self tests. That should do it. Good luck.

Fargo, ND

#22 Dec 5, 2008
I have a 99 ranger with 110K. It idles fine, I can rev it up in nuetral just fine, but when I get on the gas and hit about 3000rpm it backfires and then run fine. If im not on the gas heavy it runs fine all day. Any ideas

Nampa, ID

#23 Dec 5, 2008
ALC, either fuel pump problem (pressure regulator built into pump, small 2mm rubber ball with spring got clogged). Or fuel pump connector hose leaking in the fuel tank. Check pressure on the fuel rail, should be more than 60 psi with key on and engine running, and not dropping after engine shut.
If fuel rail pressure test is OK, it is your fuel injectors getting clogged. Don't waste hundreds of dollars on "injector cleaning" ripoff scams. Get yourself new injectors, you can find them at 50 bucks a piece.
If you change a fuel pump, go only with OEM Bosch. Others are just chineese junk, that fail in less than a year (on one the motor burned, pressure valve rubber ball got dissolved on the other). rockauto sells bosch pumps for 144, they've got decent prices on injectors too.

Concord, CA

#24 Dec 21, 2008
I have a 2001 ranger. When in park or neutral I rev the engine and at 3200 RPM's it starts misfiring on all cylinders and will not go over 3300 RPM's. Under load, as excellerating on to the freeway it will go up to 6000 RPM's if need be. At 80 MPH it starts to misfire again. My friend plugged in and analizing computer and no codes are show and the "Check Engine" light never comes on. It seems to be an electrical problem since a new fuel pump was recently installed and it passed smog inspection. Any ideas?
Dave G from Sacramento

Sacramento, CA

#25 Jan 31, 2009
I have a '99 Ranger 4.0 with 165k on it. At 118k I had an issue where it would start fine, but every 10th time it wouldn't. It seemed like I had a dead battery, or bad connection. After seeing white smoke come out of the tail pipe, I found my head gasket went out and I was burning water.
After rebuilding the engine (did it since it was apart) I put it back together and drove it another 15k to find it missing. The "check engine" light came on, and the codes said two cylinders weren't firing all the time. I changed spark plugs and wires, and everything else I could think of, and then pulled the heads. I had multiple cracks in each head. I had them rebuilt/replaced and reinstalled them. Runs great now.

Cranberry Twp, PA

#26 Feb 3, 2009
i have a 2002 ford ranger 4.0 when im at a steady speed it seems to jump like if you stall it on a start. i have new plugs in it and just put new wires last night but its still doing it. it only happens when its cold and wet out. Any ideas?

Boise, ID

#27 Feb 3, 2009
1. Fuel pump (check fuel pressure on rail, should be 55psi+, key on or idle or high rmp).
2. Fuel injectors (better change for new OEM than try to clean them).
3. Clean the IAC. It's on the driver side of the intake manifold, two bolts, one connector. Just unscrew and flud with carb cleaner. It gets dirty and sticky and causes jerking when you suddenly drop gas pedal. I cleaned mine and now it's coasting smoother.

But most likely it's injectors. Ranger injectors have small needles prone to get clogged and require high fuel pressure to pass enough gas. Cleaning them won't help for long, since the surface is not mirror polished no longer and attracts goo. For that reason, I wouldn't go with rebuilt ones. And I have doubts about how long aftermarkets made in china would last.

Cincinnati, OH

#28 Feb 7, 2009
I just put new plugs and wires in my 02 ranger 4.0 idles good but when u accelerate it misses like crazy it ran good before i changed plugs and wires whats up

Las Vegas, NV

#29 Mar 3, 2009
Minor, double check you have the correct plugs with what you pulled out. Do some research for the correct numbers or ask the dealer for the motorcraft numbers. A lot of stores (Autozone and etc) list the plugs for the SOHC as the same from the old OHV 4.0's, and they are not. The OHV are shorter and will not work in your truck. hope this helps.
04 Ranger Edge

San Bernardino, CA

#30 Apr 7, 2009
Idle Air Control Valve $50.
Jeff R

United States

#31 Jun 21, 2009
I have a 2002 ford ranger. It now has a check engine light on. Runs great when your up to speed but shakes really bad and seems to run very ruff at idle. The code says misfire is cylinder #6. I have put plug wires and spark plugs in it as well as a new fuel filter. Need help to figure out the problem. Any suggestions.???
Jeff R

United States

#32 Jun 21, 2009
I have the problem but with cylinder 6. Did you find out what the problem was ?

Boise, ID

#33 Jun 22, 2009
Both Jeffs - change fuel injector in bad cylinder (or all of them - they are ~50 buck on the internet). Easy DIY project for Saturday morning: you just unscrew intake manyfold. There is a tricky bolt holding EGR pipe by the oil dipstick: first, unscrew top nut, then use deep socket and uncrew the whole bolt. And you would need a torx socket to unscrew pins holding fuel rail. It is all straitforward, nothing to brake. You don't even need new set of intake manyfold gaskets, the old ones usually don't break and are in excellent shape.

Don't waste you time and money on "injector cleaning" scams run by automechanics. For 100$+ you can get two brand new injectors and be better off.

Saint Louis, MO

#34 Aug 22, 2009
I had a similar issue on a '97 Ranger, 2.3L 4cyl. It was a real thorn in my side. But... I finally fixed it!

Error: Misfire on cyl. 1

Symptoms: Rough / erratic idle, check engine light was on, check engine light would flash at low speeds, engine would stall at times. Ran fine, for the most part, at highway speeds.

Solution: I did the usual, replace all plugs & wires. I did a compression test and checked for good spark at each cylinder. Yet, the fix was free! Check all vacuum lines! I did a visual inspection a couple months ago, however, a vacuum line was the issue. The vacuum line on the driver-side manifold was the issue. It had slowly worked it's way loose. It looked fine, but once I touched it it fell apart. Also, check the connections on the passenger side of the block, near the firewall. There's a small black box with two rubber vacuum lines, these have been know to dry-rot. I dis-connected the battery to allow the computer to reset, reconnected and it runs like new. I hope this is able to help someone. I know it's a huge weigh off my shoulders. Who knew a 1/8" piece of rubber could cause this much stress! Thanks

Gold Hill, OR

#35 Sep 6, 2009
I have an 03 Ranger 4.0L which from time to time will misfire when accelerating or going into passing gear. I have done most of the things mentioned on this forum. Today the injectors get cleaned, hopefully this will correct the problem.

Camden, TN

#36 Sep 22, 2009
Dont know if anyone is following this anymore. I had the same problem, misfire on cyl 6, engine light flash. I had already replaced my cps because it went bad and squealed bad, replaced plug wires, plugs. My started about a month ago so I checked everything I could. Ended up I replaced my coil pack and ecm. Yes expensive but it runs good now. Got my ecm from rockauto for $308 and had to take the truck and new ecm to a ford dealership to flash it. I was told it would be a $100 but they did not tell me to bring both keys ( I was only given one when I bought the truck) and that I could have put the ecm in prior to bringing in the truck. Needeless to say it cost me $260 by the time it was done with them. Hope this helps out some.

Minot, ND

#37 Nov 10, 2009
I have a 1994 ford ranger 3.0L. it also misfires but does not throw any codes or a check engine light it is nearly impossible to drive without it stalling or lurching all over the place. i replaced the coil, cap, rotor, plug wires, spark plugs and the distributer pick up. and it ran good for a few days b4 going back to misfiring again. 3 shops could not figure it out im am looking for any advice on what to look at next
Rod Swim

Huntsville, AL

#38 Dec 1, 2009
Hey guys I can help with mnost of these problems but your not gonna like the price. Its the map sensor on the front of your intale tube thats causoing all of your idle and misfire problems. sometimes you can blow them out and then they will work fine, Then other times they have to be replaced and ford knows it and charges about $125.00 for one on the 4 litres but the one on the 3.0 litre will run you, get this $250.00

Minot, ND

#39 Dec 2, 2009
thnx for the help ill check that out

Collierville, TN

#40 Dec 22, 2009
97 Ranger 2.3 4cyl. I had #2 cyl misfire po302. 252,000 miles. Tried coils, wires, plugs, fuel injector power and injector #2 no help. Found a broken intake valve spring on the #2 cylinder, replaced all valve springs and back in action.

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