[tim si]

Ive got a 90 model 5.0 with 90,000 on it.At idle it sounds like it has a dead cyl. and tach bounces,but once i bring it up above1,000 rpm it seems to go away.Also while driving as soon as i get on it the engine seems kinda bogged down for a couple seconds then starts pulling real hard.Engine is stock.auto lite plugs,frp wires,msd coil,msd cap+rotor,walbro 255 pump.changed from speed density to mass and it does it with both.The egr isnt hooked up,could this affect it?I was wondering if i should try changing the dist.with 355 gears how close should i run with a stock 93 z28 auto?Any advice would be appreciated,thanks

[ken5_0]

where's timing at?

[tim si]

The timing was at 10,but when i converted to mass a week ago the comp.had a hypertech chip in it so it might be higher now.with the aod one time i pull out and stomp it and it will go sideways and two minutes later it wont even chirp the tires.

[ken5_0]

Use a timing light not a chip to tell you where timing is at! So does it run like duke when it is hot? If so check a plug when it is running bad if you dont have a way to read the o2 sensor when running and see if she is rich or lean. If she is rich when hot first check the coolant temp sensor.

[tim si]

Had the timing checked today and it was at 8 degrees with pill out.the guy set it at 0 .I thought it was supposed to be at 10 adv.but at 8 the valves rattled like crazy with the a/c on in high gear.what am i missing.Also egr is hooked up now and no difference in performance.seems weaker than before.It runs like duke all the time now,cold,hot,lean,rich,doesnt matter.

[tim si]

Somethings wrong with this whole thing,ill buy a timing light tomorrow and check it myself,that way ill know for sure and ill just get a temp sensor too.Thanks for the advice.

[stang fanatic]

intake temp sensor will also make it run rich or lean

[ken5_0]

Set at 0??? Do you have a stock motor? Or is it cammed? Maybe someone degreed your cam wrong? Valve rattle at 8 adv or ret?

[stang fanatic]

theres definitely a timing issue also...valve rattle shouldnt occur that low. look into possibly a stretched chain

[tim si]

It is all stock,90,000 miles and never even been into the valve covers. My #s are hard to read so i marked 10 degrees advance with soapstone a little while back.I think he might have been seeing 18 and thought it was 8 and maybe set it at 10 thinking it was 0,but i wont know til tomorrow.I know i had it set at 10 before the comp.swap.all i know is its a dog now.I can box it up and itll barely turn the tires over.A couple weeks ago ,no brake,just stomp it and it would spin all the way through first gear.I still think i have an ignition issue,im gonna grab a new set of plugs too.

[1slo5.0]

Valves don't rattle. The noise you are hearing is detonation. Fix the problem before driving the car anymore or you will have some major problems.

[tim si]

timing is at 10,with no rattle or det.The mechanic that checked it just read it wrong so it must have been at 18 adv. before he pulled it down.Its turned down way below the factory setting so the chip must be advancing it that much. waiting on temp sensor,plugs,and i think im gonna remove the chip til i can get this figured out.also gas milage went from 19 mpg to 17 mpg after mass air swap.thanks everybody.ill post what i find out if anything

[95opal]

If your totaly stock whats up with the chip? Ditch the hyper crap and bump your timing up to 12*-14*. Mail order chips are a joke

[tim si]

It came with the computer.My only experience with chips was an 85 iroc with a hypertech and it would scream.In my first post i mentioned that at idle the tach would bounce like it was missing it did this with the speed density too,but just in the last few weeks.I agree i probably dont need the chip but i plan to put a turbo on maybe this summer and you cant mod something if its not running right to start with.If i cant get it soon i may just throw a carb on it and go from there.

[IcantDo55]

Originally Posted by 95opal If your totaly stock whats up with the chip? Ditch the hyper crap and bump your timing up to 12*-14*. Mail order chips are a joke

X2

[tim si]

Took chip out and set timing at 10.Runs much better.

[eeknayspa]

My mustang had a bad fuel injector so the cylinder was not firing. You can check the fuel injectors using a stethiscopewith a long aluminum rod attached (most car parts places have them). You will here a clicking sound on those that work and nothing on the one that doesn't

[tim si]

I did check for codes on non contributing injectors and nothing showed up.I still think somethings wrong.I dont think i have as much bottom end as i should.Im going to swap intake and inj.s and ecu and see if it helps.

[ken5_0]

Is your timing jumping around when you check it? Check end play on your dampner. I just reread your first post and saw that you said it clanked at idle then goes away! I have seen motors that do the same and the thrust bearing was shot! If this is true you will have excessive end play and your timing will jump around. Check it out.