I recently replaced my spark plugs, fuel injectors, and catylitic converter. I also did a full tune up not too long ago. The engine continues to miss and feels like it is being held back under a light load. My gas milage has also dropped a lot. What could this be?
I had that issue and stuck a bottle of injector cleaner through it. Came good within 60miles. I dont use mine much (1,200miles a year) so poor fuel was my culprit, try that and see what happens.
Also did you replace your fuel filter? Sparkplug leads good? Rotor and Dizzy Cap good (that was the first thing that went on mine), Coil output okay? Did you recheck yoru plug heat range and gaps? TPS playing up?
i have replaced all the things you mentioned.
My guess: Mass Air Meter (MAS), or Throttle Position Sensor (TPS). Get the specs from your Factory Service Manual (FSM), and ohm 'em out with your multimeter. Given the mechanical design (rheostats) of this generation, they will fail eventually. And, OBDI error codes are not always definitive. In my case, I had a failing MAS.
'89 4Rnr 3VZ-E 220K
(...you DID check for the notorious bad head gasket syndrome, right? Exhaust CO/CO2/HC in coolant?)
nope i have not done the O2 sensor
When I had this issue I cleaned my MAF and the truck drove like new again... Literally. It was crazy!!!
The oxygen sensor could be the whole problem. If it gets sluggish the engine will run rich and cause the symptoms you're experiencing. If you have access to a scanner you can watch the behavior of the oxygen sensor. It should change rapidly from about 200mv to about 800mv. Hope it helps. Al snowjrmydc wrotep
I have some of this trouble on a 95 and was trolling this newsgroup hoping to find some info.
Besides being kind of anemic it idles TERRIBLE. Thats the real complaint. It does have fresh plugs, dist cap and rotor.
The code that pops up is 26 for rich condition seen by o2 sensor. It has also popped up with lean condition too. My idea was that the injectors may be leaking, but I have no real basis for this. Cleaners have been run in the tank hoping for improvement.
I'll peek at the MAS as Dante pointed out since that is one of the troublespots my scanner pointed to.
Any other ideas appreciated.
Remember to take out the trash if you want to email me.
-SP
snowjrmydc wrote:
Speedy, I had a '95 that I put 60k miles on and now have '00 Limited/SC'r with 65k miles. About twice a year I buy 2 bottles of Techron FI cleaner at Wal-Mart and run thru it. I run the 18 gal tank down to 1/4, add a bottle and 6 gals of gas, then run that tank back down to 1/4, add the 2nd bottle and fill the tank. Then I run that tank to almost empty. That gives me ~24 gals of gas to 24 oz of Techron because my tank takes 12 gals to refill at 1/4 tank. Since I have the SC'r I also have 2 step colder Iridium plugs with 40k miles on them, and I have never had a problem with idleing. My W had a '86 PU. I also used the Techron and never had a problem with it either.
Ron
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