I am having the worst time figuring this one out. I have a 92 Bronco with a 351W (5.8). I have been chasing an electrical problem for some time now. It includes replacing all the EEC relays under the hood, new ground cable (best improvement), egr position sensor, tfi module, and probably a few things I can't remember right now, anyhow, I have a stuttering problem above 1/4 throttle lately. It only shows itself after I reach operating temperature, it will ping AND pop thru the manifold almost at the same time if I lean into it. I suspect the distributor, or possibly the replacement tfi module. Has anyone seen this before and can tell me which way to look next.

Al...

 

have you pulled codes? are there any vacum leaks? your timing should be set at 10*btdc with spout connector removed. whats your fuel pressure at the rail.

 

I pulled codes and I get 512, I can't find any vacuum leaks, of course you know how they can be, I have 45 psi at the rail and my timing is at 12* btc with the spout out.

Al...

 

45 seems hi. to check for vacum leaks spray some carb or tb cleaner around hoses and intake etc.. if the idle goes up you found the leak. how do your plugs look? back your timing to 10. how many miles on this motor?

 

175K on the motor. I have had it for 4 years, it is probably time for plugs. I am hoping to try the vacuum trick this weekend.

Al...

 

While checking vacuum don't forget to see if the cannister purge vacuum selenoid valve is sticking open. Unhook the wires and jumper it to the battery and see if you can get it to stick open like mine did. It will not show up on codes. It is by the egr valve.

 

you have had it for 4years and havent changed the plugs yet? man that thing probably just needs a good tune up.

 

give it a tuneup and reset the timing. Mine was acting just like that for 3 months just because someone on this forum told me that because it has a computer it will time it's self. I believed it and never timed it. Finnaly I took it to a shop. They timed it and it has been screeming down the highway eversince.

 

Sounds like a timing problem , try as advised plugs wires and fuel filter/ tuneup then retime .Remeber the spout connector has to be disconnected before timing TR

 

Well, I tuned her up this last weekend. Put in NGK V groove plugs, cap, rotor, 8mm wires, have fuel filter, waiting for my brother to return tool. Anyhow, what a difference, it runs great now. I also put in a can of seafoam engine treatment, put half thru the intake vacuum and half with about 5 gallons of gas... Running absolutely great now. The C.E.L. is on since the treatment, but not affecting performance, going to check codes again a.s.a.p.

Thank You,
Al...

 

PLEASE post what codes you pull. I am curious as to the application of
Sea Foam........and if that could possibly cause the CEL to come on for some reason......also.....I dont remember if you said you put in a new O2 or not, but it may be better to change the O2 after the Sea Foam treatment......no?

 

thats correct use the seafoam first then replace plugs , o2 sensor etc...